Lenovo's have been solid
R61 and X201 have had rock solid wireless. The firmware for each wifi was a package available for install. I'm not sure if it was firmware-iwlwifi in both cases though definitely for the R61. I've taken to installing the other firmware packages though since they are small so I can't confirm which I used for the X201.
firmware-atheros is there also.
Granted, for wifi purchases, my first visit is the Backtrack website to confirm if the wifi is supported with full monitoring/injecting. If Backtrack supports it, you can pretty much bet that the standard drivers will be easily available for other distributions.