For 1500$ you should be able to get a good system from your local store or a big reseller. It will be a bit hard to figure out which system to get since there are some traps that should be avoided and on complete systems its sometimes hard to find out what is in it.
If you check the midrange system buyers guide at anandtech
Buyers Guide you can get an idea how the system could look like.
If the budget is rather on the low side of 1500$ then i would get a Radeon x700 graphic card (with 256MB RAM). With that an AMD Athlon 64 3200, 1GB RAM, HD, double layer dvd burner, 450W power supply and all the other stuff needed to complete it.
Biggest problem is that prebuild systems often offer super fast processor with junk around it, so when you only look at processor speed and price you might go wrong.
If you feel no urge to build the system yourself you dont have to, storebought is fine to and the extra price payed is verry small compared to the trouble to build it yourself.
OK, thats only my opinion. Keep asking and maybe we can find a path for you.
p.s. The market changes monthly. So when you think up what to buy now and then wait 2 month you have to start over again.