Need some preference advice real quick

I am going out to get a new game for the system that I built last night, with these specs.

AMD XP 3200+
512 mb Corsair XMS PC 3200 RAM
Radeon 9800 Pro 128 Mb 256 bit

Now, I was wondering what people thought. Halo or Far Cry. Halo is well, Halo, but I also really love battlefield and Joint Opps and that new graphics power I have can be seen in Far Cry better. But from those of you that have played Far Cry, is it better than Halo enough to make it worth my while? I will probably get both in the near future anyway on payday, but for now, which is the better bet.

 

I would opt for another 512 megs of RAM for any of those games. Overall game play will be so much better. Only game I play at all these days is Battlefield 1942 all flavors, though I do play DC the most. Just cain't seem to get enough. hehe