Opinions/Question

A couple years ago (when nVidia 6800 gpu first came out), i bought this computer. I was the first one to order one of these cards from the local comp store (to give you an idea of how old everything is). Fast forward to now. I have replaced misc things here and there; It has seen its better days. My HDD recently went out and just gives me a reason to upgrade instead of dumping money into something that has yesterdays technology.

Right now i have:

nVidia 6800 (cant remember brand, but MSI(?) pops into my head)
AK86-L AOpen MB
AMD Athlon 64 3000+
2 gigs ram (dont remember brand)
new 500W PSU (As it recently went out)
I dont know the name of the case, but its black/red trim and has a clear side. Lights up orange/red. Has Z in the designs

My question is, i have about 400-500 to upgrade. Would i see any considerable gains over what i have now or would just buying a new HDD be a better solution as of todays prices? The computer satisfied my needs just fine before it died but some games did push it a bit. (And i love assembling anything so it gives me that satisfaction as well.)


Also, could i re-use anything i have? (Im guessing the case, DVD drive/floppy, and PSU)
I also obviously have monitor, keyboard/mouse, OS (XP), and such....

So, comparing to what i have now, anything would be an improvement? I will look through some build threads and see what is a good set-up to go with now-a-days.

Thanks for your reply!