looking for some good bass speakers and a great subwoofer fo 600 bucks

well I've been using some altec lansing surround sound speakers running on real tek hy tek operating software and it can handle alot of bass it's just sometimes I need to edit the pitch of songs on lower ghz songs. So on the songs I look at with the extreme bass boosts I've been seeing alot of quantum speakers and subwoofers I wanted to know if there are also some that are configured for a computer or maybe have an adapter so a laptop could be plugged into the set to play songs and also wanted to know good softwares that I could bass boost some of my mp3's that I own. thanks in advance.

Adapters
http://www.compusa.com/applications/SearchTools/item-details.asp?EdpNo=4115644&CatId=4261
http://www.compusa.com/applications/SearchTools/item-details.asp?EdpNo=402124&CatId=2769
List of external adapters
http://www.compusa.com/applications/category/category_slc.asp?CatId=4261&name=External-Sound-Cards
Decent subs
http://www.crutchfield.com/p_108PS210BG/Infinity-PS210.html?tp=187
http://www.crutchfield.com/p_732ESWM6/Energy-ESW-M6.html?tp=187
Bookshelfs to match
http://www.crutchfield.com/p_108P162BG/Infinity-Primus-P162-Black-grille.html?tp=186
Or a couple floorstanding
http://www.crutchfield.com/p_108P362BG/Infinity-Primus-P362.html?tp=185
http://www.crutchfield.com/p_107TSI300C/Polk-Audio-TSi300-Cherry.html?tp=185
The polk floors & energy sub would be a sweet combo!
http://www.crutchfield.com/p_107TSI300C/Polk-Audio-TSi300-Cherry.html?tp=185
http://www.crutchfield.com/p_732ESWM6/Energy-ESW-M6.html?tp=187
Wire and Cables
http://www.crutchfield.com/p_703SUBA2M/AudioQuest-SUB-A-2-meters-6-6-ft.html?tp=2452
http://www.crutchfield.com/g_22111/Speaker-Wire-without-Connectors.html?tp=3063
http://www.crutchfield.com/g_22111/Speaker-Wire-without-Connectors.html?tp=3063
Software
http://www.dexster.net/
http://www.fabfilter.com/products/pro-q.php
http://freemusicsoftware.org/category/free-vst-effects-2/eq

Edit:I know your probably brand specific,but if you don't mind doing some installing and wiring you could build a very nice setup.I was hanging out with a friend yesterday and he reminded me about this website.
http://partsexpress.com/
You can make some nice speaker setups from scratch.They have almost anything you can think of to do builds.If I had 600 to play with I would do that.Of course saving some for the external sound card.
I would pick out a sound card first,then work from their.