Goin ATI back to Nvidia(need suggestions)

System specs: P4 2.8 with HT (not celeron)
1 Gig PC3200 Ram
Ati 9600Xt 128 AGP
Audigy 2LS soundcard
Seem to get a lot of stuttering playing BF2 on 800X600 res. and was thinking
of going with a GeForce 6600GT. I don't have a lot of money to spend and I
found this card on Newegg for $145.00. Questions I have:

1. Will this card be a decent enough upgrade for 1 year?
2. It's only 128 for memory, does this impact games?(that are out now).
3.Can it be overclocked easy?
4. Aslo saw a GeForce 6800 128MB for $164.00, would this be a better buy?

I realize PCI-E is the future, but don't want to upgrade mobo and processor
for another year. I get my computers as my dad's hand-me-downs, he does a
lot of video editing so vid cards I buy. Saving for a house and gotta stay
in cheap-mid range cards. Used to own a GeForce 4Ti4200, loved that card
when it was new and modern. Thanks