Some upgrades

[Mag-Mower]

So, I got my new computer a few weeks ago, and am dieing to upgrade it already, to something a bit more powerful, here are my current specs:

P4HT 3GHz, 800 MHz FSB
512 DDR2 ram
X300SE 128mb Hyper memory
No "Real" Sound card

So, I was thinking of adding this:

1 Gig of DDR2 ram
a 6600GT PCI-e
and a decently priced Sound card, along the lines of the Sound Blaster.

Here are the games I want to play:

FEAR
BF2
HL2
Planetisde
EQ2
UT2007
and maybe a few more. I was wondering if I should look at a Plain 7800 instead of a 6600GT, though the price difference is gigantic. Opinions please!