What to upgrade for christmas

Hello,

I am looking to do some component upgrades to my pc for my Christmas gift to myself. looking for better performance for gaming (BF3 / D3 (when it comes out) and other mainstream games) and just general usage. looking to keep upgrade in the $300.00 area. Really up in the air on what to do in terms of noticing a difference. I want to feel I got something for the $300.00 upgrade that won't feel outdated in two weeks. Just components to my system not trying to build a new rig ground up or anything just switch some components. Thanks for any ideas.

current system
AMD Phenom II 955 black (O.C. 3.7 ghz)
G.SKILL 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1333 (PC3 10666
80 gig boot drive (western digital 7200 rpm)
250 gig (storage 7200 rpm)
XFX HD-577X-ZNFC Radeon HD 5770 1GB 128-bit DDR5 PCI Express 2.0 x16 HDCP
ASUS M4A77TD AM3 AMD 770 ATX AMD Motherboard
corsair H70 water cooler for CPU.
Samsung 22" LCD