You'd like the Z5500's. I have the Z5300's and they're THX certified 5.1's. Unless you plan on actually putting speakers behind you, (which can be tricky when you're using a computer setup and not your living room tv) then go with 5.1 speakers. The extra 2 speakers might jack up your price and may not be required. I guess it depends how much of an audiophile you are. Also, you're going to get a slight buzz with ANY sub, mine I can't hear unless I crank it up and put my head up closer to it. Turn the volume settings up on your computer before you turn up your power output on your speakers. That helps to reduce static noise. Also, good sound is user-defined. Some people prefer treble to bass, so expect to tinker with your settings too if you're looking for top quality sound. Try onboard sound too before buying a sound card to see if it serves your purpose. Onboard sound (in my opinion) sounds pretty good, but will probably be clearer with a sound card. Still, top Creative sound cards run $200 or so, and there are other brands out there you should consider. Read reviews, do your research and understand what you're spending your money on, even if you have plenty of it.
I'm also a fan of Samsung Monitors... I own the 215tw and the 204B, but there are newer models out now. Get a nice widescreen with 8ms response or faster for gaming. I might even say 6ms or faster now. Good video cards should be able to adjust resolution to standard on-the-fly if your game doesn't support widescreen (most non-new games).
Here's a good place to start if you want to see some Samsung monitors. I think they're great quality and uber-sexi. I prefer mine without speakers as it sometimes brings the cost down a bit, and the small speakers sound far too tinny. Extra's like component jacks on the side that I can plug a gaming console into are nice too.
=SAM]http://www.pricegrabber.com/search_attrib.php/page_id=37/vendors[]=SAM
Oh, and my center speaker fits nicely right on the stand under my monitor. My whole computer matches with black/silver/blue. It looks really sexy.
Blue LED's in a Thermaltake Kandalf Case
Logitech G15 gaming keyboard
Razer Copperhead Mouse - Blue lit
Samsung 215tw monitor
Logitech THX Z5300's
Black leather chair from Meijer $60.
Everything matches beautifully and even the mouse is tops.