Both the 650's and 800 are just ridiculously good with mainline - you can't go wrong! If you do ever pick up the latter though, make sure you give sorrodje's hd800 "french mod" a try, as described elsewhere. It is derivative of what Senn did with the hd800S but costs about $10 and takes 5 minutes to install. Way better than the old style anax/damping mods. Congrats again on scoring George's lovely build, and welcome to the summit and the thread!