Budget PC build

[Blacklabel3]

I'm looking to upgrade my older PC but I've been out of the PC hardware game for quite some time now. Need some help deciding on parts. I'm looking to spend under $500 dollars, quite a bit under $500. $300 would be awesome.

My main goal is to be able to run games the games Starcraft 2, Diablo 3 and Starwars: TOR in high or max settings with decent FPS. Not something like 15 FPS, more like 30-40 (or more) FPS.
Some other games I'd be interested in running on this machine would basically be all current and upcoming Blizzard and Valve titles, Crysis 1, X3 games. I don't expect to be able to run the higher end games like Crysis 1 on max settings with decent FPS, I just like to be able to play them with moderate settings and without "pain in my eyeballs" FPS.

I already have a decent monitor, speakers keyboard and all that. I'm just interested in the tower and internal components. Some parts from my older PC that I'm considering re-using are my old Ibuypower gaming full ATX case, Works 430w PSU and I have an older drive loaded with Windows XP. I'd like to re-use as much as possible to keep costs down.

So, If it's reasonable to re-use that stuff, these are the parts I'd need

Processor-
Motherboard-
RAM-
Graphics card-
DVD burner-
Secondary big HD-

Can someone help me fill these slots and keep it close to my price specifications while meeting my performance requirements?

In case anyone is curious the machine I'm upgrading from has 2ksomething+ single core AMD Athlon XP, Windows XP, AGP GeForce 6200 and two 75gb HD's.
I've been playing games on my Xbox 360 for years and do most of my computer work on my more recent HP G-60, Vista, AMD turion x2 laptop. I did manage to play WoW on the old desktop and then on the laptop for quite some time, though.

 

[Blacklabel3]

You can get a brand new cpu for $450 built on here by toms best and brightest that will run great and salvaging parts isn't always a good idea especially if you want to have good fps on sc2 at decent resolutions. Some of your old components like the psu might be a system killer for newer more powerful components.

O, Alright. I was wondering if the my old PSU was going to be enough. If it's for sure not going to do the job, I'll add that to my list of parts I need to get.