Bands that everyone compares other bands to

The Jesus And Mary Chain
Slowdive


(More often than not, you will find that any Shoegaze or Shoegaze friendly band will be compared to either Slowdive, My Bloody Valentine or The Jesus And Mary Chain; especially by those who have limited knowledge of the genre.)
fall out boy.
The Smiths
The Clash
pavement
The Stone Roses
the who
Big Star
The Band
Wilco
Nirvana
Television (even though the comparison tend to be off)
Kitchens of Distinction
Gee, Jaguar. Leave some for the rest of us. I was going to say The Beatles, which is kind of obvious, I suppose, but you beat me to it. Any pop/rock band with two-part male harmonies is inevitably "Beatlesque."

Personally, I'm guilty of comparing way too many bands to Radiohead.
Coldplay
coldplay, really? i thought coldplay was always compared to u2, rather than a band that was compared to other bands?

speaking of which, i'll list u2 as my band that other bands are always compared to.
sad but true. Reviewers mention the Coldplay comparisons all the time.

Best line from "40 Year Old Virgin": "You know how I know you're gay? You like Coldplay"
oh yes, that's right, how could i forgot the " you know how i know you're gay" sequence.

though nothing beats the "man o lantern." :D
Oasis