Questions concerning HDTV, PC's and my setup

Ok, first off I will list the full setup I have. I really don't know where to put all these questions and since my PC doubles as a Blu-Ray player, I feel most can be answered right here. Thanks for any help before hand and sorry for the wall-o-text crit.

THE SETUP:

Sony Bravia 52" HDTV 1080p
Western Digital VelociRaptor WD3000GLFS 300GB
XFX GX280NZDF9 GeForce GTX 280 1GB 512-bit GDDR3
ASUS Black 5X BD-ROM 12X DVD-ROM 32X CD-ROM
OCZ Platinum Edition 4GB (2 x 2GB) 240-Pin DDR2 SDRAM DDR2 1000 (PC2 8000)
XFX MB-N780-ISH9 LGA 775 NVIDIA nForce 780i SLI Intel Motherboard
Intel Core 2 Quad Q6600 Kentsfield 2.4GHz 2 x 4MB L2 Cache LGA 775 Quad-Core Processor
Antec TruePower Quattro TPQ-1000 1000W
Microsoft Windows Vista 64-Bit Ultimate
Logitech MX518 1800 dpi Gaming-Grade Mouse
Logitech G15

PROGRAMS RUN ON THIS SYSTEM (NORMALLY)

Fraps
Coral WinDVD 9
Mass Effect
Bioshock
Call of Duty 4
Oblivion: Elder Scrolls
World of Warcraft
Warhammer Online
Crysis
Left 4 Dead
Counterstrike: Source


During playback of movies, the resolution is insanely pure and clean, no hiccups. During game play, most of these aforementioned titles are hindered with screen tearing (especially Mass Effect and Oblivion).


THE QUESTIONS:

1) Would buying a second graphics card and running in SLI fix or even eliminate the screen tearing? Or is this a matter of the monitor?

2) Would anyone recommend that I buy a regular computer monitor for the gaming, and build a second computer for the media playback for my TV? (I have alot of parts readily available to make a lesser computer, albeit one that can run a blu-ray program and have a good display)

3) Is there possibly a different bottleneck that would be better to fix than simply buying another graphics card?


Thanks for any feedback and again, sorry for having such a long winded post.

Do you have your Bravia set to 120Hz or 60Hz for gaming? 120Hz will cause input lag because that mode causes the HDTV to create interpolated frames, but I'm not sure if it will also cause tearing.

Never played games on my TV for awhile 'till last week and what I thought to be ghosting is infact the shadow from the game. I came to conclusion that my Sony TV is fast enough for fast games.