A bit more obscure (at least in the US maybe), but I heard “We Are Each Other” on a radio in Canada and immediately assumed it was Barenaked Ladies. No, it was The Beautiful South, from England. The funny thing is, those bands are each other, with BNL’s humor swapped out for the South’s scarcasm.
Beautiful South = P.D. Heaton, former singer of the Housemartins, who has that same kind of warbly voice as Steven Page from BNL. Would be an easy mistake to make.
Until just a few years ago, I thought that Baby Come Back was a Hall and Oates song. Never even heard of Player.
I like that song:
I keep your picture
Upon the wall
It hides a nasty stain that’s lying there
It’s funny. I also like R.E.M.'s homage to 10CC, Star Me Kitten.
You’re crazy, it’s obviously a Hall an…wow, it’s really not! :eek:
See, I thought the group that did “Horse with No Name” did “Heart of Gold”.
Hey, I was seven. Shut up.
Remember “A Girl Like You” from the Empire Records soundtrack? I swore up and down that was David Bowie. Nope.
I thought it was Iggy Pop until I saw the video.
I always thought Blinded By the Light was a Manfred Mann song covered by Springsteen.
I learned that “Horse With No Name” was by America. Then I picked up a second hand copy of a tape by America. And so I just figured Neil Young was once a member of America.
For a while I thought that “All For You” was Blues Traveler instead of Sister Hazel.
I think everybody thought that. I guess SH was more of a one hit wonder, but I still can’t remember which is which without some serious thought.
When I was a kid, I thought Ticket to Ride was a Carpenters song covered by the Beatles. Blame my mother.
Out of all the examples posted here, I would say that this one and mistaking Andy Kim for Neil Diamond on “Rock Me Gently” make the most sense.
What was particularly weird about the latter example is that Andy Kim had had a couple of previous hits singing in a completely different style that bore no resemblance to Neil Diamond at all.
If you played them back to back with RMG, there is no way you would guess they were the same vocalist.
First time I heard the song Girl Like You(never met a girl like you before) I thought “oh, cool new David Bowie song.” Never heard of Edwyn Collins.
After seeing Ferris Bueller’s Day Off I told a friend,
“I like the parade part where he sings Danke Schoen but I’ve never heard that version.”
“Oh, that’s Wayne Newton.”
“No, no. It was a different version. I know what Wayne Newton sounds like.”
“But it’s Wayne Newton.”
“No, this was sung by a girl.”
“Yeah, that was Wayne Newton when he was younger.”
“Whaaa??”
I remember the WFBQ dj saying “this is not Pat Benatar, it just sounds like her” when introducing Quarterflash’s first single.
I’ve met several people who think “Don’t Pay the Ferryman” was Styx.
I’ve cited this one many times, but… the first 20 or 30 times I heard Bonny Tyler’s “It’s a Heartache” (around 1978), I thought it was Rod Stewart.
I used to love a lot of Billy Preston’s funky synthesizer instrumentals, like “Space Race” and “Outta Space.” When the Commodores first came along with “Machine Gun,” I was sure it was Billy Preston.
And what’s funny is I think Rod Stewart did a version of that song too.
I just remembered another one. For a while it drove me crazy that I couldn’t find out who did “The Breakup Song”. I thought it sounded like Bryan Adams, but I didn’t see it on any of his albums, and I never heard of the Greg Kihn Band.
I loved Rod Stewart’s early 80s hit “Bette Davis Eyes.” 
Bryan Adams? That’s just silly. It was clearly by John Cougar (Mellencamp).
During the Napster days, I was pulling an all nighter stealing music and ran across an mp3 labeled David Bowie/ Don’t You Forget About Me.
Hmm, must be some rare track I’ve never heard of.
Excitedly downloaded it only to hear Simple Minds while I envisioned Judd Nelson walking away with fist thrust into the air.