I'm not going to pass judgement on either.....but since you mention F.E.A.R. you should read this click here
Whatever card you get...make sure it has 512MB onboard video memory.
For the record I have a P4 (S478) 3.2GHz cpu with 2GB RAM and a Gainward BLISS 7800GS+ (a full blown 7900GT in AGP form ) which has 512MB onboard memory.
Just updated from an ATI X800XT with 256MB memory.
At its best playable settings the game suffered from periods of bad stuttering with fps dropping to below 10 fps.With the Nvidia card I can play smoothly at the following settings:
1280x960 resolution with 2x AA,16x AF,soft shadows switched off and everything else at maximum quality.......no stuttering during actual gameplay and frame rates always above 30fps (via FRAPS).
That's the sort of settings you can expect to use with either of the cards you mention.....so look for 512MB onboard....It's worth the extra coat with F.E.A.R.