It might have been said already, but you do know the 300
8 is out? It's better in every way over the 3007. I see you already have the 3007 now though lol...
But the 3008 has WAY more inputs:
1x VGA (Analog)
2x DVI-D (Digital) with HDCP
1x HDMI
1x S-Video
1x Component
1x Composite
1x DisplayPort
And it can display more colours. Even if it's more expensive, it's still worth saving up for over the 3007 because it's so much better.
I've run my 3008 on a 8800GTX and 9800GX2, not had trouble with any of them playing anything. But i've not tried Blu-Ray or HD-DVD. However because the 3008 has HDMI i use my PS3 on it over that, and Blu-Ray looks really great.
Theres a thread on it
here.
Also about HDTV vs a 30" monitor, i have a 46" HDTV (1080p) and the 3008 craps on it. Yes 1080p material stuff has to be scaled to fit 2560x1600, but because there is way more pixels on the screen than with a 1080p TV the scaling is
extremely good. I always use my PS3 and 360 on the 3008 over my two 1080p HDTV's because it's just better. Each of my 1080p TV's cost atleast 2k aswell so they're not exactly crap ones. I find with every single person who says otherwise has never used a 2560x1600 monitor, so just ignore 'em.