Since I don't feel like spending upwards of $900 on a completely new system, I was hoping I could salvage some parts from my friend's old pc that he used for gaming. I would like my new system to be capable of running games, like WoW, at medium settings minimum, as well as the ability to run multiple apps at once without lag.
Here are the current parts (I don't have a complete system):
I'm willing to upgrade some of the parts if necessary, like the mobo/cpu, but I want to try to minimize costs. If I had to cap the price I'm willing to spend to upgrade, I'd say $400-500. What's the best I can do within this price range? Should I get another stick of DDR2 ram, buy all new DDR3, upgrade the processor to the new i7 series, motherboard? I think my video card is suitable. Obviously I need a HD and case. I was hoping for a smaller case, that runs quiet and easily fits my videocard.
Also, it would be nice if I wouldn't have to upgrade for a few more years after this.
That will let you upgrade to newer AM3 CPUs in the future. LGA775 is a dead-end as far as upgrades go, there are no more new CPUs being released for it.
Personally, I would go for the second option, even though it's a bit more expensive. It offers much better upgrade options and will give superior performance now, meaning you won't have to upgrade again as soon as the first build, and you will end up saving money in the long run, as the next time you upgrade you will probably have to get a new motherboard and DDR3 RAM anyways. If you were willing to spend an extra ~$30-$40, you could grab a Phenom II x3 720 processor instead. Better multi-tasking, and will perform better in games due to being able to offload background tasks onto the third core, leaving two just for the game.
You could keep your 9600GT, but with how cheap 4850s are at the moment, it would definitely be worth the money to get one.
I can agree with the idea of keeping your current board and chip overclock that chip for some more power, up the memory to 4 gb, maybe 8 as it's cheap. The 9600gt is a good card, I've got one myself, but grab a 4870 or so, put the 9600gt on ebay, and be happy. Maybe double check the PSU as well and be sure it can handle what you want to do, but the 775 socket while dead, still has some powerful chips, no reason in my opinion to spend more than necessary. Then pocket the rest of your money, or spend it on some games and be happy.