Want to fully upgrade my PC

Hey fellas, back again. After the help I got from my last question and riding the random link train from one page to another :dance: it dawned on me that I should just altogether replace my aging PC parts in one go (partially because of the x-mas deals...well actually that's like the main reason I guess. DON'T JUDGE ME!) Anywho, I got 500$ give or take and looking to just buy myself an awesome present with a little help from you really handsome/beautiful internet peoples :thumb:

PC specs are:

Win 7 Pro 64
GTX 560ti
6gbs DDR2 ram
AMD Phenom 8850B Triple-Core
Hitachi 500gb HDD
ASUSM4A785-M

(And I live up here in Canada)