Help with parts for decent gaming machine

[Dwardom]

I have compiled a list of parts that I have considered buying in order to game on my $400 budget.
I play games like WoW, SWTOR, SCII, League of Legends, and more importantly, I anticipate playing Guild Wars 2.
I am not demanding 60 frames per second at maximum graphical settings, but rather a comfortable 30 or more at medium settings.

If you would not mind, please critique my shopping list and assist me in correcting any errors I may have made (be it in connector type, compatibility, whatever it may be).

Motherboard and CPU:
http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=849391&srkey=b69-5381

Video Card:
http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=612914&srkey=a271-6770

Memory (Running 32 bit XP, so 3gb max):
http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=4837614&srkey=c13-8220

Power Supply (still considering a case with an integrated 500W supply:
http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=7220650&srkey=t13-2511

This was made with respect to my $400 budget (I will be getting the power supply covered as a birthday gift, further lowering the price)

What sort of performance can I expect to get with this hardware?
I apologize that my first post on this forum is asking a favor, I hope you guys don't mind. ;D

Thanks!

 

[claptonman]

Overkill on the PSU and it is a terrible brand. 550w is all you need for this setup.

http://www.newegg.com/Product/Product.aspx?Item=N82E16817371030
http://www.newegg.com/Product/Product.aspx?Item=N82E16817151094

 

[Dwardom]

I am plenty willing to change the PSU.
Other than that, does it look like it will run what I want at the settings that I want?

 

[claptonman]

Yeah, you'd be fine at running those games at those settings.

 

[Dwardom]

Would I by chance be able to stream my own gaming by chance with the power I'll have? (on own3d.tv or twitch.tv)