stuff like the network teaming has been on HP servers for years now. it's OK and useful only if all your machines support it, they are fast enough to handle the data and you have good network equipment to handle the bandwidth. For my PC at home to play games on and learn SQL it's a waste since my SDSL tops out at 1500 both ways and even if I go to FIOS when it comes to my area one gig-e port is still overkill.
Anandtech said they didn't see any improvement with LinkBoost. Other TCP/IP features are questionable since there is so much stuff between you and other online players. I'll see what others are saying before I think about upgrading to the next level.
If you want SLI, get it. But I wouldn't buy anything above a 550 for the other features.
I think the speed race topped out for now in terms of CPU speed and when AM2 is near the end of life or games start to really support multi-threading I'll get a dual core CPU. For now I bought a 3200. And I'll replace the ATI 1600XT I bought with something new when the whole physics accelerator thing gets straightened out and some clear standards emerge.