Skullzz--Glad to see I'm not alone in my liking of Killswitch Engage...
For getting into Opeth, my recommendation of a starter album is Blackwater Park. After that, my suggestion is to try and get My Arms, Your Hearse and Deliverance/Damnation (get these two together). After this, get Still Life. If you find yourself liking those, you may want to try Morningrise. Get Orchid last if you become a really serious fan.
Anyway, most of what I listen to is not metal (I am one of those infamous Damnation fans!), but there's a bit in there. My tastes are ALL over the map, so expect lots of oddball stuff you didn't think you'd ever see mentioned on an Opeth board!
Metal:
Opeth
Killswitch Engage
A bit of Symphony X
Metallica's S & M concert
May end up buying a Thrice album, we'll see
Classic rock:
Pink Floyd and solo works (particularly Rick Wright. But compare Mikael's voice to David Gilmour's, and Steve Wilson's to Rick Wright. Interesting...)
Talk Talk/Mark Hollis
Peter Gabriel
Jeff Beck
Steely Dan
Some Talking Heads/David Byrne
Some Led Zeppelin
Some Moody Blues
A bit of Stevie Ray Vaughan
A bit of Rush
A bit of Billy Joel
A bit of Black Sabbath
Other modern artists:
Sigur Rós
Enigma
Coldplay
Radiohead (although their most recent albums aren't so hot)
Mogwai
Some Loreena McKennitt
Some Marilyn Manson (hey, I don't care what people think, I enjoy what I enjoy)
Other artists:
Aaron Copland--classical
Beethoven
Bach
Igor Stravinsky--classical (seriously, "Rite of Spring" is the closest thing you'll get to metal in the purely classical world, in some places.)
Steve Reich--classical (modern)
Michael Kamen--film score composer
Hans Zimmer--film scores
Other miscellaneous film scores
Miles Davis--jazz
A bit of John Coltrane--jazz
And a few other miscellaneous albums here and there I haven't mentioned. But to sum it up, I seem to like almost everything that's not rap or country.