Quad-SLI is a little extreme for a 24" LCD. A single 7950GX2 is pretty damn fly.
Sell all the speakers. You say you have a huge room? How big are we talking? 20x20? 30x30? No matter how big the room, you will find a single quality sub that will do the job better than 3 multimedia-pc-designed subs. Or go dual sub - that's been done before. Three is just too weird a number and you will have to really know how to set it up properly.
Sell the speakers/sound card. Buy a good 5.1 setup. Buy a low-mid end receiver (Harman Kardon, Yamaha, Denon etc.). Get a XtremeMusic. Not enough bass? Get another sub. Leave it there.
Go to a quality audio store: Paradigm, Monitor Audio, Infinity, JBL, B&W...there's tons of good speaker companies.
Things I find overkill with your setup:
4 Gigs of RAM. Go with two. Seriously.
Creative X-Fi Elite Pro. An XtremeMusic will be fine. The Platinum if you want the I/O console.
Quad-SLI. If you still want it, make sure you use tons of SLI-AA to get some of your money's worth.
Raptors are pretty damn useless. Sell them. Get a RAID card from Areca. Get two more Caviars. RAID 5 for the win.