Horses by Patti Smith is top drawer.
Stone Roses self-titled first album is a superb debut, albeit not in the same league as Horses - just thought I’d mention it since they announced they’re re-forming for a couple of concerts v recently.
“August and Everything After” by Counting Crows.
I was born in 1961, so a lot of my favorite albums were already “classic rock” by the time I started paying attention to rock music. It’s hard for me to judge how fresh or innovative many albums may have seemed when first released.
Still… even though the overall quality of the album is mixed, I have to think ***Are You Experienced? ***by the Jimi Hendrix Experience was the boldest, most innovative debut album by any rock band at any time. I can think of numerous BETTER debut albums (or, at least, numerous debut albums I like better), but none that was more likely to make people say, “WOW- I’ve never heard anything like THAT before.”
Boston
Yet he was still a teenager.
Velvet Underground deserves a mention at least.
The Band
How can they all be the best? 
My pick: Elvis Costello, My Aim Is True.
mmm
So many candidates, but I’m going to go with The Decline of British Sea Power by British Sea Power. It’s got uptempo rockers like “Remember Me” along with sweeping epics like “Lately.” (Those latter two are YouTube links.) It’s at times literate, explosive, angsty, and abandoned, which makes for a perfect rock album.
Their follow-ups are good, but don’t compare to Decline.
A tie between The Doors and Bat Out of Hell. The latter gets my vote because all the songs were written by a single person–the genius that is Jim Steinman. And it is the best selling album with that attribute.
Boston for sure. Shame nothing else they did lived up to it.
Bat Out of Hell was technically Meat Loaf’s second album.
You win the thread.
X-Ray Spex - Germ Free Adolescents
They appeared, made arguably the best punk album ever, then broke up almost immediately.
Trick’s first record had a couple of good songs but was largely ignored.
Or did you mean ‘In Color’, which was there 2nd album?
My vote as well.
Ill go along with Appetite for Destruction. For the last 10 years, I will take Costello Music by The Fratellis. Shame they imploded so fast.
My World 2.0
[ducks & runs]
The first thing I thought of when I saw this topic was “Boston”.
Also, much as I love Bat Out of Hell an argument can be made that it wasn’t his first album.
Another vote for The Doors self-titled debut album.
Not eve my favourite debut rock album (That would probably be Pearl Jam’s Ten) but the influence The Doors had is unsurpassed by any other debut. No question.
I vote for The Doors as well.