Everyone seems to be posting about extreme bands...they're quite 'big' here in England, but I'm a big fan of Portishead (try Wandering Star, Roads, Glory Box)...they're kind of like Massive Attack but not...if that makes any sense...
...so yeah, trip-hoppy...
Good English band - Eden Maine - try Ephemera or Cold Light...people call them progcore...heavily influenced by Converge...
www.edenmaine.com
Godspeed You Black Emperor! are brilliant, I think people in here've probably heard of them, it's better to buy an album rather than listening to individual tracks anyway...it's kind of 'space rock'...ignore my labels, just check out the bands...
Aereogramme are a very cool Scottish band, try Post Tour, Pre Judgement or Zionist Timing...it's like indie with screamy parts...very pretty...
Mahumodo are unbelievable - try California or anything else you can get off their site...you will fall in love...
www.mahumodo.com
I also suggest Isis and Old Man Gloom, but I suspect a lot of you already know and love them...if not get The Other, Celestial (The Tower), The Beginning And The End, Deconstructing Towers, or Carry by Isis...or Hot Salvation by OMG
Anyway, I'll think up more soon...hope there's something new there for you to digest...