**I need help buying a new system!**

Ok, I was researching hours and came to a conclusion that the athlon 64 x2 is superior over pentium d. After going through numbers of forums, I saw some praises about ibuypower. And after I saw the price of the systems on their website, I just couldn’t believe my eyes. Are they credible? Does the system last years without breakdown? I’ve used my dell system (pentium 4 1.4ghz) for over 3 years and it was good to me. I am expecting same durability for my new system. I am thinking about buying a system for about $1500.
I will be using mainly for grahpic design, video editing, audio editing, and maybe some 3ds. I am expecting to use my new system for about 3 years. Also, I want to know if there is drastic difference between athlon 64x2 and pentium d.
Did anybody have a chance to use both systems, if so, what did you think about them? Thank you.

(ps) I’m most likely to buy pre-configured system.