The first to consider on memory is what the board actually supports and the type of memory you can run even with a slightly faster speed. If your board runs only 184pin dimms that is the memory you are limited to. For running a faster dimm you would install that into the first dimm slot on the A channel with the slower on the first on the B. One thing to add here is that single sided dimms will be incompatible with dual sided dimms as well as having different memory timings.
As far as makes of cards many seem to prefer the XFX brand while I look at eVGA, BFG, MSI especially, and a few others. Since I have been running mainly cards with ATI chips lately someone else will have some other suggestions to throw your way there. With the games like Prey, Fear and it's expansion pack, Half Life 2, and some others I run those at high setting at the 1280x1024 screen resolution even in Vista with a lower end card. The MSI Radeon X1300 Pro 256mb PCI-Express isn't any high end model but does the job here. I look at reliability over performance mainly.