The man speaks the truth.
I personally think the monitor is possibly the most important part. Buy a widescreen monitor (or 2!) and the pleasure of using the PC increases a lot.
The very least I would get is a 19" widescreen, ideally I would get a Dell 2007FPW or a Phillips 20" or a NEC 20". They all run things perfectly... I know you want to get the better graphics card and so on, but you could always get a basic card, and then in a few months when DX10 cards come out, grab a the next gen card. an 7300GT or something is about 50 and will see you thru till then.