I don't know, I've always liked Poison The Well. You Come Before You was a fun album, if not seminal (did you guys know seminal also means "consisting of semen?"). It's difficult to toss out hardcore recommendations, because the genres around that particular influence have been muddled far too much.
--I would definitely recommend Alexisonfire: all of their albums are pretty accessible, but Crisis is just a continuation of Watch Out!.
--Fear Before The March Of Flames. I recommend this to everyone. Very experimental, and The Always Open Mouth is absolutely fantastic.
--At The Drive-In and Fugazi. Duh.
--Converge! You will not like Converge on the first, or tenth, listen. Once you like them, you love them.
--Bear vs Shark. I like Bear vs Shark. You should too.
--These Arms Are Snakes. If you like FBtMoF, you might like TAaS. You might not.
--The Sounds Of Animals Fighting. Actually worse than Converge for inaccessibility. Good stuff though.
--Blood Brothers. Ditto above.