Compare the processors here. Considering I have never owned a DELL or a pre-built since 1994, I would think your new DELL should kick some serious Packard Bell butt.
I guess if you really want to go for a prebuilt Dell XPS have the better range in terms of an enthusiast. You may wish to consider swapping that Q6600 for a Dual Core (E8400 if possible) Since at stock you'll see better performance in your games, and heck do you really need more then 2 cores?
Are you going to be salvaging any parts from your old board?