What do I need?

[oscark]

So I need to buy a couple of custom computers. All they need to be able to handle is poker (and 1600x1200 resolution on a 2001FP) and the accompanying programs that go with it (PT, HUD, etc). I am looking to get away as cheaply as possible, for something of decent quality which will do what I need. Living in South America, it appears the following are my basic options (I know basically nothing about computers):
Processors:
AMD Duron 3.4GHZ
Athlon AMD 2.4GHZ Sempron
Athlon AMD 2.6GHZ Sempron
Intel Celeron 2.4 GHZ
Intel Pentium IV 2.2 GHZ
Intel Pentium IV 2.8 GHZ

I have a couple choices of brands for boards (don't even know what that is or if it is important):
Board Asrock
Board Duron
Board PC Chips Athalon
Board Intel
Board Foxcom
Board Biostar
Board MSI K8MM

For Ram, I assume I need 512? Or is 256 enough? (It is DDR, which I assume is fine?)

As far as a video card, can I just go with whatever is included or should I upgrade? Those available include:
Radeon 64MB AGP TV OUT
PCI Express 256 MB ATX X300
Geforce 128 MB TV Out Exp
Geforce 256 MB TV Out Exp
T Video ATI Radion 9250 Dual 128 MB

Anything else I should be concerned about?

Thanks,

Oscar