Tweaking my budget build ($800) w/intel i5 or i3

I'm currently building my first gaming computer, and I'm looking to keep it under $800 (including monitor, Windows 7, and cheap keyboard). Unfortunately, my current build without a monitor, keyboard, or Windows 7 is around $950.

I've tried downgrading certain parts, but I can never seem to find the right balance that is under $800, and still runs games on lower to medium settings, such as battlefield 3 or modern warfare 3. I am looking for some help as to which parts I can change out to save a few bucks.

EDIT: I will not be doing any crossfire or SLI business, I have yet to look into it, unless it will save me some cash. I will probably be overclocking however.

Here's my build so far:

CPU: intel core i5-2500k quad (possibly i3-2100?)
($270)

Mobo: Gigabyte GA- Z68AP-D3 intel z68
$70

RAM: Corsair Vengeance 8gb (2x4gb) ddr3
$45

HSF: CoolerMaster Hyper 212 EVO Universal CPU cooler
$35

HDD: Seagate 7200rpm 500gb SATA-6G 16mb
$110

PSU: Corsair TX v2 enthusiast series 650watt (I figured I can downgrade this, but I was having trouble)
$80

GPU: ASUS GeForce GTX 560 Ti (definately need to downgrade, need one that will run bf3 and mw3)
$245

DVD: (no problems here)
$20

Case: CoolerMaster HAF 912 mid (possible new case)
$60

Basically, I think I can downgrade my CPU to an i3-2100, and my GPU to something lower, but I can't seem to pinpoint anything that will run as solid as I'd like it. I know it's a lot to read, but I really appreciate anyone who takes the time to reply, so any help at all is appreciated more than you know, thanks in advance.

I took all my prices off Tiger Direct, I won't look for the best bargain until I know what parts I'd like, but here are the links (in order of the list above) for convenience:

CPU: http://www.tigerdirect.com/applica [...] CatId=6988
Mobo: http://www.tigerdirect.com/applica [...] =G452-1047
RAM: http://www.tigerdirect.com/applica [...] CatId=4534
HSF: http://www.tigerdirect.com/applica [...] No=1284316
HDD: http://www.tigerdirect.com/applica [...] CatId=2459
PSU: http://www.tigerdirect.com/applica [...] u=C13-2800
GPU: http://www.tigerdirect.com/applica [...] CatId=3585
DVD: http://www.amazon.com/dp/B0033Z2BA [...] -2011.html
Case: http://www.tigerdirect.com/applica [...] No=6531504

Well, as far as the ideal gaming CPU, here is one recent and sort of relevant thread that may help a little...

http://www.tomshardware.com/forum/ [...] g-question

From what I've read, the i3-2xxx line is good for gaming, but not for overclocking (can they be overclocked at all? I don't know). If you are probably going to overclock, you'll probably want the 2500K, which is only listed at $220 on NewEgg; the TigerDirect link you provided directs to a listing for the locked-down, non-K i5-2500 (which, I guess can be oc'd just a little bit, even though it is not "unlocked" ).

I don't know if you can downgrade your psu too much; if you are going to overclock, and run a 560 ti or even something a little less, than you don't want to go much less than maybe 500 watt psu; there are on-line psu calculators, I don't know how accurate they are, but they may give you a good idea of your power requirements.

i5 2500k for the win

Run the prices on all your original stuff again. The 2500k is down to $210 so that is $60 off the price right away. That would put you at $890 without comparison shopping for other stuff.

Try looking on Newegg too.

There are some 560 TI deals this weekend only on Newegg that are $215 base price with $30 rebate which is another decent chunk gone from the total.

An XFX 550w on Newegg is $70 base with $15 rebate right now, so that is another chunk removed.