This is well worn areas. I couldn't tell if your router has current firmware, if a driver for your Vista was current and which encryptions you tried. WPA2 is indeed busted until you get a patch from Microsoft so you need to know that some have to call it in. Microsoft may kick you back to the machine's maker so be sure to call whichever is free first.
Hope this helps,
My Dell notebook is set up as follows:
Intel Next-Gen-Wireless Card
Netgear WNR 834B
Originally the only connection I could get was to the router with limited connectivity (no internet). After hours with a friend in IT I have an internet connection. Strangley we couldn't get a connection when we secured the network so we just allowed my notebook mac address access. Now everything seems to be working fine except my download speed sometimes drops to almost nothing occasionally. I always have an excellent connection. It seems to be random.
I have read some other forums where there are suggestions that the drivers for the Netgear WNR 834B are not yet toatlly ready for Vista although it is advertised that way.
Any thoughts out there?