No, you can't do hybrid crossfire with an nVidia card. The last cards that did hybrid crossfire were the old 40 shader 3450s and you could hybrid crossfire those with the 760 and up IGPs. No point though, since even a cheap 4650 or 9500GT is alot faster.
the 5670 seems to be the best value. at that price range.
I will probably just use the built in video for now to keep costs down on this particular system.
I am actually just trying to build a really inexpensive system that still performs well.
I am helping my friends by building systems for them while I go to school for computers.
it would be nice to be able to do something in the low $200's but i know that's tough.
What are the rest of the components? Have you considered using one of the new Llano processors? They have built in graphics processors that are rather competent for gaming at low resolutions and they also allow for hybrid crossfire that is actually worth using if you get a low end HD6000 card later on.
EDIT: BTW, outside of what I just suggested above hybrid crossfire is basically useless and not something worth thinking about.
The Llano chips are basically Athlon II x4 processors with the added video processing power. I haven't read much about their overclocking ability or this SSD problem you mentioned. An HD6670 or HD6570 is what you would want to use with one for hybrid crossfire if you find the built-in graphics unacceptable. If I remember properly it would add roughly 25% extra performance to either of those cards.