Waiting is never bad, but if you're going to upgrade now, that rig seems fine. I'm always afraid of upgrading/building a new system, and then before I know it, there's new stuff/cheaper old stuff. >_>
yeah thats what i do upgrade about once in every 2 years. or i up grade a little at a time e.g im waiting till the 2900xtx comes out before i start thinking about buying a new dx10 graphics card