What games can I run smooth with this build?

Alright I'll list the parts im going to buy from newegg and tell me if i should go with something different and why? im on a 700 dollar budget so this was the best i could do. List what games i can play with this build or what games i can play if i just change it a bit

CPU: AMD Athlon 64 X2 6000+ 3.1GHz - $ 92
Is this good enough to run this?

MOBO: GIGABYTE GA-MA78GM-S2H AM2+/AM2 AMD 780G - $ 80


RAM: G.SKILL 4GB (2 x 2GB) 240-Pin DDR2 SDRAM DDR2 800 - $ 55


GPU: SAPPHIRE 100226L Radeon HD 3850 512MB 256-bit - $ 89


PSU: CORSAIR CMPSU-650TX 650W ATX12V / EPS12V SLI Ready CrossFire - $ 100


Hard Drive: Seagate Barracuda 7200.10 ST3400620AS 400GB $ 50


Case: COOLER MASTER Centurion 5 CAC-T05-UW Black Aluminum Bezel , SECC Chassis ATX Mid Tower Computer Case - $55

OS: XP Home edition - $ 90

------------------
Subtotal - $670

I wanna stay under the price of 700 dollars now here are a few other questions

1.Should i go with vista instead of xp for direct x 10? or is xp better performance overall for current games?

2. Do i have enough psu wattage?

3. Should i go with a diffrent processor? i like the amd mobos instead of the intel

4. Any other better amd mobos?

5. Is everything here compatible with eachother? if not? list why it isnt and what can i get for similiar price range

Thx guys hoping to make the purchase within a week or so

i think you should invest more in Graphic card
you will feel its lake with that GPU
if you can, try hard and get the hd4850, I Found this one with 2x2 OCZ RAM combo
http://www.newegg.com/Product/Prod [...] =10&page=1
for 15$ less
the PSU is very good you will be good too if you downgrade to the vx550w but keep it
for the OS
go with anything you want but 64bet

1. Go with Vista Home Premium 64 bit for $100.

2. That 650w is more than enough.

3. Intel has better performance, especially when overclocked.

4. At about that price range the 790GX for AMD, check combo deals.
http://www.newegg.com/Product/Prod [...] 6813138128

For Intel the P45/P43 boards.

5. Truly a bad choice at that price range for a graphic card. The HD3870 is a much better choice, so is the HD4670 on the ATI side. On Nvidia the 9600GT is better, but can't be used in crossfire.
http://www.newegg.com/Product/Prod [...] 6814131095
http://www.newegg.com/Product/Prod [...] 6814127383
http://www.newegg.com/Product/Prod [...] 6814125099

If you go a little higher, a HD4830 or a HD4850 on ATI side or a 9800GT on the Nvidia side.

The Antec 300 is a great case, it's $54 but it has free shipping and it'll probably save you a few bucks. It has a combo deal with the EA 650w Earthwatts power supply which drops the price to $55 with free shipping
http://www.newegg.com/Product/Prod [...] 6811129042

http://www.newegg.com/Product/Prod [...] 6817371015

if you're not going to crossfire, then you can get the Antec Earthwatts 430w and save an extra $25 or so (may not have free shipping)

*edit* the reason i suggested the 790GX is that it supports 8x/8x crossfire, an upgrade path you may want in the future.
It's also featured in a combo deal with this CPU for $20 off Athlon64x2 6000+ Windsor 89w
http://www.newegg.com/Product/Prod [...] 6819103233

With the HD3870 you could eventually get another one in the future and crossfire them for better performance then the HD4850 or the 9800GT+

Proximon is spot on , that's probably the best what you can get from the suggestions. Maybe look at a P45 chipset though.

ASUS P5Q Pro LGA 775 Intel P45 ATX Intel Motherboard
This would allow you to add a second HD4850 if you want. For about 20$ more than Proximon linked.

Thx for all the suggestions loving it helped me alot