Try microcenter if you have one near you. i5 2500k are on sale there and if paired with a board like MSI h61 you can get both of them for about ~200 (CPU+Mobo) rest you can choose part that correspond to your needs.
Newegg has been selling gskill ripjaws 8gigs very cheap on shell shocker once every other week. (Between 35-40 dollars for 2x4gb kit)
As far as graphics are concerned, since you will be upgrading your monitor later on its best to get something powerful. But do not spend too much on it. Most graphics around $150-$200 will play almost all games at full settings specially on 1400x900 resolution.
Invest in a good psu but goodness doesnt = wattage
a good 550 w psu is much greater than a 1000w crappy psu.
Case is your choice as you are gonna be looking at it everyday. I personally like Antec but thats totally your decision.
If you are not a serious or extreme gamer , any good 7200rpm drive will suffice like WD black or samsung F3's . If not try one of those Hybrid drives instead. (ex. seagate momentus xt 500gb) It gives you best of both worlds. If not you can always get a sub $100 SSD with about 60-64gb capacity featuring sata III
Whatever you build out of the options given by fellow members, its all gonna be good. They are all plenty fast for gaming. Doesn't make much difference provided you are not a serious gamer.
I have played Crysis 2, NFS HP, Assassin's Creed: (All of them), Dirt 2 etc all on high setting with a C2D e7300 @ 3.4Ghz and 4 gigs of ram with 8800gt in sli . No lag or loss of quality.
So with what you have most games wont be an issue.
Just my opinion