Supertones, that is the one. Well outside of Relient K, I haven't really listened to any of them. I can't really say I'm a big music person. I have always been a really big Weezer fan and listen to a lot of them. As of late, I have picked up liking The Beatles and have been listening to a lot of them too.
But some of my favorites from Relient K are: I'm Lion-O, can't say I don't like it a whole lot because I remember watching a lot of Thundercats back in the day; Pressing On is also good; Maybe Its Maybeline, mainly because it is so dang catchy; For the Moments I Feel Faint, really good song; May the Horse Be With You, kinda along the same lines of Maybe Its Maybeline; and there are some others I just can't really think of a whole lot of songs at the moment.