Past or present, bands that never really made it but you think should have been more successful than they are/were. My choice are King of the Slums. Clever musically and lyrically, they got lost in the Madchester scene in the late 80s. http://www.youtube.com/watch?v=QEXeDG_HSQk http://www.youtube.com/watch?v=jCZSB_ktU8c Still listen to their excellent album 'Barbarous English Fayre' which you can download for free these days.
Go ahead and buzz 'round the ears I've been growing that one braid back there for years I've had it since the first time I saw Queensryche The front may conform to society But the back says I have personality Even if it's really really, Even if it's really really bad. - I've Got an Ape Drape, The Vandals. Best song ever written about Mullets.
Good call on Interpol mate cracking band. I'd also like to add The White Lies, British Sea Power and Rocket Science (youtube them) to my list.