This. In a corporate environment wifi just isn't allowed. We have it in our office but it is stunted beyond reproach. You need to be plugged in to access stuff.
Not all large corporations are like that. Here at Cisco most employees are given only laptops (Thinkpad or MBP) and the wireless here is usually fantastic as one would expect. Now if only I could get my hands on a Cius...
Rumors abound of a Sandy Bridge- based Air hitting later this year, along with Thunderbolt — if a Thunderbolt to GigE adapter comes out, it will remedy this issue.
802.11n can be pretty fast and I doubt you'd notice a difference vs a 10/100 network. Many gigabytes of video files get transfered OTA every day in my office.
I transfer every day large files between my mac and my pc or NAS and the transfer rate would kill me.