Love Nvidia's stuff, only chips I use. Couldn't pay me to put in an ATI card again. I prefer Gigabyte, XFX, BFG. Asus, MSI, PNY, EVGA are o.k. and have decent reps. Stay away from Jaton, BioStar, Sparkle, Zotac. For dual 16xx's, entry level Datacad cards would be something like a GeForce 8400 with at least 512MB ram. A 8600, 9600 or 9800 at a good price would be mugh better. I don't know much about the 210 line but they should be comparable to the 8400-9600 performance wise. For dual 19xx's GeForce probably want to step up to 768MB ram. If your gaming
bump up to a GTS 250 or GTX 260, or really go nuts in the 400 or 500 series. (drool) You can compare the tech difference info
here The model numbers can be a bit confusing so make sure you have a good idea of what your looking for. For example a GeForce 5500 is better than a GeForce 6200. For Datacad and general desktop performance, start with the memory amount then a good core speed & memory type (DDR3,GDDR3,5 would be ideal) are probable the base of what to compare when shopping.
3D rendering in most high end rendering apps will benefit from a Quadro card, but I admit I am not up to date on what the line carries these days. Don't know how much Sketchup may benefit from one but I'm sure our good friend Google can help find out.
Another important item to check into before you take a plunge is make sure you have an adequate power supply for the card you are looking at and have the correct socket type on your board. If your still using a AGP x4/x8 mainboard finding a compatible card might be hard and finding a good card with 512MB might be even harder. They have a few at Newegg.com and BestBuy usually carries at least one model and sometimes even a older PCIx1 version. The PNY AGP stuff was always pretty good. Well gotta get back to work....