did you not see my hardcore appreciate thread?
Regardless, goto
http://soundandfuryfest.com/
almost every band on there is a classic.
Gorilla biscuits, terror, rotting out, warhound, death threat, Crowd Deterrent, Life for a Life, Dead End Path, Soul Search, Defiant, Hundredth, Harms Way,
Check out bands on Seventh Dagger Records for scary militant straightedge such as xTYRANTx
Or bridge 9 records for things such as Foundation and etc.
Just use your head, its really not fucking hard
On TUI's label, Reaper Records, theres Naysayer, and a few others that are great.
Check out No Sleep Records as well