I now understand why nuttkase doesn't feel most of the stuff I suggest. Well atleast we agree on Thursday & with that being said I think you should start with Thursday. It's very hard to tell you wich Thursday CD to pick up first, you're better off just downloading a few songs and from there deciding.
If you want some hardcore music I suggest Bring Me The Horizon, Parkway Drive, Shai Hulad, or August Burns Red.
If you want something a little less hardcore and more melody then try From Autumn To Ashes, (my favorite band) Hopesfall, I Killed The Prom Queen, or Poison The Well's Opposite of December CD.
If you like Thursday then check out Funeral For A Friend, Alexisonfire, Thrice, and maybe even Finch.
If you want something that is underground even as a genre then check out some Screamo such as Circle Takes The Square, PG.99, Funeral Diner, Raein, Saetia, Ghosts, Amanda Woodward, and The Saddest Landscape. Screamo is my favorite genre but it isn't for everyone, it's rather poetic & experimental. Alot of instrumental calms instantly followed by insanely complicated breakdowns. And lets not forget most of the bands have 2 vocalists going off at once.
If you want just some instrumentals to relax to then check out M83, Red Sparowes, Ghost & Vodka, Explosions In The Sky, & Sigur Ros.
If you want some straight emo to listen to then try The Blue Hour, Saosin, Last Days Of April, Shutterfly, or Northstar.
As for goth music if you want goth goth then try Jack Off Jill, Scarling, Switchblade Symphony, Black Tape For A Blue Girl, Mira, Xandria, or Poison Black. (and of course THE CURE!!!!!)
If you want industry goth then go with Collide, Razed In Black, Oghr, Skinny Puppy, or Tweaker (chris vernne sp? of NIN)
For Death Metal, Opeth, Katatonia, My Dying Bride, Sirenia, or Dead Blue Sky (emo mixed with death metal)
and lastly if you want pop music then try Story Of The Year, Evanescence, Strata, Chevelle, HIM, Cradle Of Filth