Quote -   I have heard that ati and intel work well together while nvidia and amd  are a good fit. I dont know if any of that is true.

leave it to the comp manufactures to come up with that one especially when ati is owned by amd  lol.

Any how my 2 cents, I just got;  the new Gateway 6000fx with the i7 and an ATI 4850 hd. which could be a sweet system if you can get past all of Gateways never ending failures. 
With this card my render speeds are great I've rendered 1000 hq renders in Daz using render throttle and it took about 3 hours. seems to run depending on the scene anywhere from 1- 20 seconds for the render. poser of course takes a bit longer.

I myself prefer the ATI video card. for this type of application. I seem to have multiple problems with nVidia while using Daz, it's seems nVidia does not handle openGL as well as ATI
either way poser still crashs and burns less than 200 frames into an animation set on preview, with the new service pack that is supposed to prevent that.

I do tell you though this is the first comp I've seen that can handle running Daz, poser, photoshop, flash , windows media player and 20 open internet pages and applications all at the same time without lag.  :o)