I believe I sent you this setup, but it didn't cost $839.
AMD Athlon 64 X2 3800+ Manchester 1GHz HT 2 x 512KB L2 Cache Socket 939 Dual Core Processor $295
http://www.newegg.com/Product/Produc...82E16819103562
DFI LANPARTY UT nF4 Ultra-D Socket 939 NVIDIA nForce4 Ultra ATX AMD Motherboard $123
http://www.newegg.com/Product/Produc...82E16813136152
AMD Opteron 165 Denmark 1GHz HT 2 x 1MB L2 Cache Socket 939 Dual Core Processor $326
http://www.newegg.com/Product/Produc...82E16819103588
If you wanted an extreme processor for a little more, go with this one. It can overclock like no other and the core is based on the FX-60 which costs in the thousands. It will still work with the DFI mobo I listed above.
You would be in pretty good shape if you chose any of those processors and the DFI mobo. I would wait to upgrade, though. AMD will be coming out with new cores and sockets soon. The socket 939 system will still be good for quite a while after the release, but if you want the latest and best, wait a while and see what comes out.
By the way, who is Garry? (I'm Chris, if you forgot)