I actually used to like this band, and I can't believe I am saying this, but I cannot stand Dream Theater.
I dunno, I just kind of started to listen to other bands out there and when I recently came back to listen to them again, it just started sounding weak to me. Didn't sound right
I also never got the hype for Avenged Sevenfold. There's a couple awesome songs by them, but most of everything else from them sound mediocre
DT are definitely an acquired taste. They are probably my favorite band :D
There's too many bands to list that I dont like, but I'll make a short list that's sure to get some flames started . . . Amon Amarth Slayer Avenged Sevenfold Children of Bodom Slipknot Korn Deftones Iron Maiden Five Finger Death Punch Mudvayne Rammstein Static X
Most more "modern" Metal bands, like Avenged Sevenfold, Korn, Slipknot, 5FDP... these bands don't have any interesting guitar parts and riffs. A7F and 5FDP are just some kind of Pop music with distorted guitar, and Korn / slipknot are trying hard to be aggressive.
A more interesting topic would be bands you love that everybody hates. For me that would be Cradle of Filth. At least everyone I know seems to hate them.