Sell all your stuff (but save the pro apps) on eBay and get an iMac... what Scates said.
The new iMac is more than competent at running all the pro apps (hell, my 1.2 Ghz iBook does a fine job with Adobe CS), and you'll make several people happy with some gently-used Apple gear. Spend all that extra money on Flickr pro accounts for your friends (
), a gigantic hard disk to store your photos, and a kick-ass SLR camera.