Shugi, do you remember that codec some one posted a few months ago for Vista that would disable it's periodic search for additional wireless connections? It actually helped quite a bit in Vista, and I've noticed that Windows 7 has a constant search going, or it seems like it, I haven't been able to truly test it just yet.
If you remember where it's at, it may not be a bad idea to post it in the OP. I'm still looking for it, and if I find it I'll let you know.
Have you seen any codecs like that developed for XP or Windows 7? It may also not be a bad idea to include Ashampoo in this OP as well, because it works even with Windows 7 now and it can help a lot of lag for many players.