Certain bands sound alike enough to me that I always associate them with each other in my mind – and with no other bands. Even if there are other bands that sound more similar, they are not as popular and so have not invaded my subconscious.
Examples:
New Order - Depeche Mode
Psychedelic Furs - Echo and the Bunnymen
Coheed and Cambria - My Chemical Romance
Big Star and T. Rex always seem like two sides of the same coin to me, even though they don’t sound that similar.
I’m not sure if I associate these bands because I think they sound alike, but these pairs stick out for me:
Nirvana - Pearl Jam (both “grunge”)
Oasis - Blur (both British)
Rolling Stones - Aerosmith (both have ass-ugly frontmen)
Boston and Kansas
Forgot about Boston and Kansas – maybe because I don’t particularly like them.
Which reminds me:
Toto and Styx.
Keane and Coldplay.
The Rolling Stones and The Beatles. Not for their sound, just their timing.
I’ve almost associated Keane with Snow Patrol, but haven’t heard enough of the latter to firm it up in my mind. While they remind me of Coldplay as well, thankfully I also haven’t heard enough of CP to make that association.
Beatles and Stones are almost linked, too for the reason JS mentions, but fall just short of connections in my mind.
Reo Speedwagon and Styx
Boston and Aerosmith (because Aerosmith is from Boston).
My connections are based more on what was together on mix tapes we traded in high school than any actual musical logic. WARNING: Late '80’s flashbacks ahead:
KMFDM and Ministry (“the industrial ones”)
Gorilla Biscuits and Minor Threat (“the straight edge ones”)
Depeche Mode and Erasure (“the gay ones”)
The Cure and The Smiths (“the angsty ones”)
The Dead Milkmen and The Violent Femmes (“the funny ones”)
The Mighty Lemondrops and Echo and the Bunnymen (“the english ones”)
Fugazi and The Red Hot Chili Peppers (“the crazy ones”)
The Who and The Kinks.
The Kinks and The Who (the mods, who at different point in their careers were accused of ripping off the other)
Journey and REO Speedwagon (corporate rock’s twin towers)
OMD and Pet Shop Boys (I have no idea why these two are forever linked in my mind. Timing?)
Ratt and Poison (The rat poison connection is too hard to ignore)
Rick James and MC Hammer (connected by their respective biggest hits)
Pansy Division and Extra Fancy
This one only works one way… When I hear the name Vanilla Ice, I always think of Queen/Bowie, but Queen or Bowie alone don’t trigger a Vanilla Ice connection.
Judas Priest and Iron Maiden: Epitomized British heavy metal; same instrumentation (2 lead guitars, bass, drums, and vocalist); the two bands I listened to most in high school.
Heh, I almost said The Cure and The Smiths, too, except that the one-hit-wonder Blue Clocks Green (“Just Like Hemingway”) sounds exactly like The Smiths, so prevented that association from taking hold. Come to think of it, “The Sound of Settling” by Death Cab for Cutie would do it, too, in its Smiths-ness (haven’t heard anything else by them, and oddly enough The Postal Service sounds nothing like The Smiths.)
The only band that I’ve ever heard that actually sounds like The Cure are The Warlocks (singing like The Cure but with slightly less depression and music the same but with more hooks,) but no popular bands have such a strong association with The Cure or The Smiths than each other.
The Beach Boys and Jan & Dean.
Lily Allen and Lady Sovereign. I’m not the only one who confuses them; Amazon lists Lily’s album under their entry for Lady S!
Barenaked Ladies and They Might Be Giants.
Both goofy, nerdy, and not taking themselves too seriously.