Help need Advise new build

im pretty new to building so here it goes

im going to be using this build for gaming and school research (when needed)

my budget is $500-600 max i will by keyboard,mouse, and monitor separately.

as far as overclock,raid,and crossfirex i will be doing them much later when ihave more knowledge about them but i need a system now because what i have now is about 7-8yrs old lol cant take it too slow

so far this is what i have (want it to last atleast 3-5yrs)

CPU: Phenom II X3 740

MOBO: MSi 790X-G45

RAM: G.Skill Ripjaws series 4GB

GPU: XFX Radeon HD 5770

HD: Samsung Spinpoint F3 500gb

Drive: dont know kinda want something that can play blueray but if budget cant afford it then its ok

PSU: dont know any quality once im guessing id need 600-700 for future overclock and crossfirex

Case: antec threehundred illusion black?

pretty much i want the "best bang for your(my) buck"
if there are combo deals pls let me know

thank you for taking your time