I just began using a new Lenovo T60p that came pre-loaded with Windows Vista Business. The machine is wonderful, and is easily the best experience I have had with Windows Vista to date.
Recently I started noticing some reliability problems with the built-in Intel 3945ABG WLAN card, and this is a big deal for me because I use wireless nearly 100% of the time. The problem was sporadic, but it would happen when moving between locations and bringing the system out of Sleep or Hibernation mode. The wireless card would be in a powered off state, and the only way to get it working again was a reboot.
After some digging, I realized that Vista was installing version 10.6.0.15 of the Intel driver for the card by default. This version has some known performance and reliability issues, and Intel recommends that version 11.1.1.11 be installed. So far, simply updating the drivers has saved me from any unnecessary system reboots.
Intel PRO/Wireless 3945ABG Network Connection driver download page