This may sound utterly rubbish, but I upgraded from Win 7 beta to build 7057 (I think) this week. I ran as an upgrade rather than clean install. Almost as soon as I'd upgraded, I started to experience intermittent problems with my wireless connection and the network troubleshooter had to reset my adapter for me to reconnect.
I noticed that the adapter generally failed whenever I was downloading more than one large file at any one time - bizarre - but sometimes it just conked out on me.
Anyway, I happened to notice that my AVG firewall couldn't start because it couldn't communicate with a "device". I used the online technical support to delete some NDIS(?) file and then reinstall AVG and reconfigure the firewall for the home setting while disabling the Windows firewall.
I've just managed to download about 5 100mb files simultaneously and the network connection has remained intact.... for now.
Fingers crossed eh?
Oh, I'm on a Dell inspiron 1520 with a Dell 1390 wireless adapter.