The difference between HC and non-HC is the gamut. The HC displays 92% of the NTSC color space. It's not too useful except in print-target media or if you work with the adobe rgb color space a lot. The color will be slightly off for most things unless you use an ICC profile (digitalversus
has one available). I'm not sure if the original 3007 is HDCP compliant, but I know the HC version is.
The 3008 apparently has a scaler built in, so it accepts other resolutions and inputs. The 3007 has no scaler and afaik, can only display 2 resolutions (1280x800 and 2560x1600) over DVI. This isn't a problem if you're only using it as a PC monitor as your video card can do the scaling for you. However, if you want to hook up a console or the like, you'll be limited to 720p. The 3008 also has a bunch of other input options other than DVI-D. I'm almost 100% certain that the 3008 and 3007wfp-hc are the same as far as the color space goes. 1080p is 1920x1080, so movies are going to be scaled one way or another: either by your monitor or your video card. I'm not certain if the 3008 can do 16:9 resolutions, but it should be able to at least do 1:1 pixel mapping. This will leave small black bars at the top and bottom of the screen since the monitor itself has a 16:10 aspect ratio.
If you're upgrading to Nehalem or similar, you should be just fine with the 4850. It'll probably last you at least 8 months before you feel the pinch by new games. You may try finding a review that features the min fps of the games you play to see if the 4850 is enough. Every review I've found has the 4850 with perfectly playable fps though.