Hey I just built 2 of 3 systems that my friends bought... I will have build notes and benchmarks soon... I will post some stuff here and on the trueopinions.com site.

Specs AMD Athlon 64 3000+:
Asus K8V Deluxe
2 pc2700 512
1 wd 160gig ide
9800pro 128mb
aspire turbo case
Total was around $900 I think(I didnt build this one...)

Specs AMD 2500+:
Aspire Turbo Case
Shuttle An35N Nvidia mobo
512mb pc 2700
western digital 80 special edition ide
liteon cd-rw
fx 5200
Total was about $600

Specs Intel 3.2 E;
Asus P4C800
1 gig dual channel kit ocz
western digital 160 sata
Asus 9800 XT 256mb
Antec PlusView1000AMG(Same case as the Pimputer)

Total is just over $2500  I am building this next wednesday....

From what I have read that are great...  However for some reason, I think it is because the dude that built the computer didnt use a fresh copy of windows, it is really slow... I mean it got beat by a 2.6GHz intel...   The only thing I am going to say is wait for the 939... If you buy the 754pin processor you are really limiting what you can upgrade and what technology you get... I dont expect anyone to release a 754 pci express motherboard ever...       If you can just bairly afford to buy the motherboard and processor dont buy this setup....  You need to get some really good ram, a sata hard drive, and a decent video card to see the results that all of the benchmarks are talking about.

Yeah the 64's do run windows xp 64 edition but the driver support and the software itself is fairly unstable...  My guess is that it will become better as Microsoft devoted more time in the coming months... Actually it is faster for game if you run the game in regular xp rather than the 64 bit version.