Yeah in many games the 8800GT beats the 8800GTX or is right behind it, and uses way less power and its faster in CUDA apps, such as F@H. The only advantage the 8800GTX has over the 8800GT/9800GT is the 768MB ram...and TRI-SLI but theres a 9800GT from ASUS which does in fact support TRI-SLI.
Theres also a 128SP version of the 9800GT, which basically makes it an 8800GTS 512.