How much heat, noise and cost?

I'm about ready to upgrade my old Geforce2 GTX, with a newer card, it's
been a while obviously since I upgraded the vidcard. I haven't really
played games in a while (I'm picky about what games I get excited
about). I'm looking to upgrade to a mid-priced card with Pixel Shader
1.1 support or higher, possibly an Nvidia 6600-series or ATI X600/X700
series.

The game I'm thinking of picking up is Black & White 2, and the
requirements say it needs Pixel Shader 1.1 support. I expect the maximum
resolution I'll be doing is 1152x864. Obviously, I want some adequate
performance, but I don't care about ultimate performance. To me the more
important factors are these:

(1) cool'n'quiet operation, i.e. low fan noise. I don't want a chipset
that's been overclocked to high-heaven to win all benchmarks, with a
blowdryer for a fan. Last thing I need is something adding several
degrees to the whole system temperature, requiring more fans.

(2) Price/performance, what's the best bang for the buck? I want to know
how important the following would be: 128MB vs. 256MB? Value-end chipset
(6200/X200) vs. mid-end chipset (6600/X600)?

Yousuf Khan