Please help, first build in a long time, low budget ($550)

hello, this is my first post as well as my first build in about 6 years so I pretty much have no idea what to look for or what i'm doing. My powermac just broke down and i don't have $1500 laying around to buy one so i'm just gonna build a pc, hopefully. Anyways, i was going to go to a website like cyberpowerpc.com but i heard too many bad things and most people just say to build your own so here I am. Here goes.

case: RAIDMAX SMILODON Extreme Black ATX-612WEBP 1.0mm SECC Steel ATX Mid Tower With 500W PSU - $94.99 ($25 rebate)
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

cpu + mobo: Intel Pentium E5200 Wolfdale 2.5GHz + GIGABYTE GA-EP43-UD3L(combo) - $144.98
http://www.newegg.com/Product/ComboDealDetails.aspx?Ite...

ram: G.SKILL HK 4GB (2 x 2GB) 240-Pin DDR2 SDRAM DDR2 800 - $42.99 (will this ram work with the mobo i chose?)
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

video: XFX GS250XYDFC GeForce GTS 250 512MB - $129.99 (is it worth it to spend $15 more for the 1 GB version?)
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

hdd: Western Digital Caviar Black WD5001AALS 500GB 7200 RPM - $59.99
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

cd/dvd: LG 22X DVD±R DVD - $22.99
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

I have a copy of windows xp which I'll be using. Besides that, do I need anything else besides whats on my list? Thanks.

This build costs about $550 including tax. any input/ideas would be greatly appreciated. I'm a total noob with computer builds and this is my first one in a long time, I'd really appreciate the help. I definitely want to keep it under $600 including tax. I'm going to be mainly using it as a graphic workstation and for gaming. Also, I was wondering if i should go for a cheap case and a decent PSU. I read the reviews and heard mixed things about the psu. I read so many good things about the Smilidon case and especially that its noob friendly which was the main selling point for me. THANKS!