I have an early Van Halen record. It’s a promo that didn’t have there logo on it. The label has Elmer Fudd on it and it was pressed from red vinyl. Paid $3 for it at a garage sale.
I have a copied tape from the vinyl of the original version of “La Di Da Di” by Doug E. Fresh and DJ Jazzy Jeff. In the original version, they took a sample from Sukiyaki, and apparently they ran into copyright trouble so all the versions today have that part cut out. However, a friend of a friend had the original vinyl. I had to run around town for 3 days to find a working record player, and then dubbed it to a tape. I still have the tape, but I’m afraid to play it because it’s a bit damaged. Just having it is enough for me.
Imho, I have a duty to preserve it and I should put it on the Internet someday.
Ohh hell yeahh… damn i remember when it had the sukiyaki sample…
I have a cd of a British three piece band called Stress… its a helluva cd… http://en.wikipedia.org/wiki/Stress_(Neo-Psychedelic_band)
Yep. One legit copy, and two counterfeits (one on black and one on colored vinyl) that are credited to Jethro Tull. I’ve never understood why some bootlegger went to the trouble of making excellent quality fakes of this single and then “corrected” the most famous thing about it.
The first “classical” LP I ever bought was an album of electric guitar (plus rhythm section) Bach transcriptions titled Jazz Guitar Bach, credited to André Benichou and his Well-Tempered Three. Released by Nonesuch, whom you’d expect to be above such shenanigans. 
I have a gatefold copy of Buckingham Nicks. Is it rare? I also have the later non-gatefold re-release.
Just yesterday I found a copy of Cher’s Heart Of Stone album, on vinyl, with the original artwork that was withdrawn after the first pressing.
I also bought lots of used CD singles yesterday (about 150) and sitting in one of them was a copy of Kylie Minogue’s Other Sides EP, which was an Australian HMV exclusive in 1997 - I only have the disc, but if I had the case I could get about $250.
Kylie’s album Let’s Get To It, which is now out of print.
I have a Spice Girls promotional CD which is apparently worth about $250-300, which was given to me for free from a Record Exchange.
Promo singles for Bjork’s ‘Who Is It’, Darren Hayes’s ‘Crush’, Eminem’s ‘Sing For The Moment’, Kate Bush’s ‘Rubberband Girl’ and ‘Moments Of Pleasure’, Mandy Moore’s ‘In My Pocket’, Michael Jackson’s ‘You Rock My World’, Missy Elliott’s ‘We Run This’, Space Cowboy’s ‘I Would Die 4 U’, Destiny’s Child’s ‘Jumpin’ Jumpin’’.
A few Donna Summer albums that I think are hard to find on CD.
The limited edition bonus disc of Janet Jackson’s Design Of A Decade collection, housed in it’s own case.
That’s just out of my CD collection, I have quite a few things I’ve picked up on vinyl over the years but I’m not sure of their worth. Remind me to organise that vinyl collection properly one day.
All on vinyl (nothing earth-shattering, I know):
Patti Smith bootleg of a live performance including ‘My Generation’
Jethro Tull Stand Up where they all stand up when you open it
Beatles White Album on white vinyl
Rolling Stones Sticky Fingers with zipper
Elvis Costello Live at the El Mocambo
Some Jimi Hendrix album that I’ve never seen listed anywhere
Lynyrd Skynyrd ‘flames’ cover
Grand Funk Railroad Shinin’ On with 3D cover and 3D glasses
Lou Reed’s first solo album
The original Concert for Bangladesh (in a box)
Rolling Stones Some Girls (there were different color patterns / cut-out faces issued - I have the one that is most rare)
mmm
Sex Pistols “God Save The Queen” 45 on A&M records. I paid about $100 bucks for it years ago, it’s surely worth 5 times that amount now at least.
I don’t know about objectively rare, but the box set by Cramps Records called “Futura,” a four-disc set of sound poetry recordings, was pretty hard for me to find.
I have whichever Secret Policeman’s Other Ball album has the live acoustic version of “Won’t Get Fooled Again” on it. Going by how long it took me to find it, I’m guessing there may be only one in existence. 
Is it Kiss the Sky? I think that’s the one I have that I’ve been unable to find on CD anywhere. It’s got one track that I think may be unique to that album, an alternate take or some such.
I have a (non-mint) copy of the original “Radio Free Europe” single by REM, released when they were still an indie band. I also have Harvest editions of Pink Floyd’s Meddle and DSOTM (i.e. those released soon after CDs became popular)
On vinyl, the original “Tongue Cover” version of Poison’s “Open up and Say Aahhh.” On CD, the original “Cop Killer” by Body Count. Both purchased by me on the first day of release.
Is this a zombie thread if it was only two years idle? Not that I care.
For a long time, my rarest CD was “Sunrise” by Bob Brozman (the greatest living guitarist who most people never heard of) and Debashish Bhattacharya (India’s premier slide guitarist). Beautiful music and jaw-dropping virtousity by both artists. A bonus was the booklet which had superb liner notes. CD had a very limited release in 1998 on an Indian label, and nearly every disc was defective (according to Brozman himself). Before they disappeared from the market, I went through about ten copies before finding one that played all the way through without hiccupping. It’s one of my VERY favorite records.
Two or three years ago I learned that it had been re-released. Found it on Amazon, bought one. Plays perfectly, but the new packaging has no liner notes at all, beyond track titles. Last time I checked it too is no longer available.
Don’t know how “rare” it is but I have the Decca 45 of the Stones “I Wanna Be Your Man”; pretty beat up, English disc with built-in hole reducer to accomodate lp spindles.
"Touch" by the group of the same name. (LP) The fancy cover with double gatefolds, and faroutandgroovy poster of Cypress Point (Monterey) with blue nude women floating in space. The music is wonderful and was a year or three ahead of its time (1968).
"Blade Runner" the bootleg OffWorld Records double CD of the never released soundtrack album. My favorite movie score. Terrible sound quality, but breathtaking music. The various official releases of the BR soundtrack, combined, don’t cover even half of the material.
Kate Bush second album Lionheart. What? You say “That’s not rare at all!”?
This is the pressed, but never actually released first US pressing. The album was not actually released in the US until after her fourth album The Dreaming. The copy I own was one of a handful rescued by the guy who had the job of destroying them.
That, and The Kick Inside - on 8-track.
Turns out I already posted this two years before.
For me, it is Martyn Bennett’s Mackay’s Memoirs. I own one of the last remaining CD copies, which I got by donating to the Martyn Bennett Trust a few years back. It’s now available digitally, but there are no more CDs available.
I collect Marx Brothers albums (go figure). The rarest, or at least the oddest, one is I Never Kissed an Ugly Woman: Twelve Stories in Song, a collection of Groucho songs.
It’s not listed on the discography at marx-brothers.org.
I never even knew where it came from until I just looked it up. Apparently it’s a Groucho Marx bootleg, on the The Amazing Kornyfone Record Label. This page calls it very rare.
I normally don’t buy bootlegs: I’m old school on artist’s rights. It just never occurred to me that anyone would do such a thing and Marx Brothers stuff is released on such obscure fan labels that the amateur appearance didn’t trigger any alarms. Weird stuff happens.
A buddy of mine in town is a big vinyl guy - at least 4,000 lp’s. People who know him give him boxes of old lp’s when they are looking to get rid of them.
A couple of years ago, he was given a box of classical guitar lp’s - Julien Bream, Christopher Parkening, etc. Not his thing, but he never turns anything down. Going through them though, he was floored: there was an original, first pressing of the Beatles’s US first record - it was on Veejay records, an obscure label because they couldn’t get anyone’s attention in the US. And it included a couple of tracks that Veejay wasn’t allowed to include, which led to production being stopped and a second pressing getting made. So that first Veejay pressing is one of the rarest Beatles vinyl - more than the Butchers and Babies cover…
I think he sold it for $20,000 to help fund his daughter’s college education ;).
I have a bootlegged copy of Madonna’s “Blonde Ambition” tour in Australia, digitally enhanced; excellent sound quality. AFAIK it’s the only one of its kind.
I have similar discs for The Red Hot Chili Peppers and Live.
I had a cassette of Vs. by Pearl Jam that had the original title “Five Against One.” I had it when I first started listening to them but I spilled Coke on my bombox and threw the tape away before I knew what it was. 
Prince’s Black Album (before it was pulled from the shelves).
Body Count (Ice-T)'s Cop Killer ditto
and a 78 of Enrico Caruso