AutoCAD Graphics Card

[Timaphillips]

This is probably the hardest topic I've tried research as of lately. I'm running AutoCAD 2007 LT and do 3D design with Sketch Up 6 for work (Yes, we use Sketch Up over AutoCAD's 3D). Sketch Up gets pretty sluggish when the design becomes larger. I can see this will be a really annoying problem that will lower my productivity as I continue. Can someone please recommend a card for my to put in my computer? I can't decide whether it's better to use the FireGL cards (made for 3D) as opposed to the new ATI HD cards. Also, we don't want to spend $1,000 + on a graphics card. We're not making movie graphics here. Keep it to $450 max. Maybe $500 if it makes a difference.

System Specs:

Windows XP SP2
Intel Core 2 Duo 6400 (2.13 GHz)
2 GB RAM
ATI X1600 512MB GDDR2