I don't have this problem (mba 2010, firefox)
joec1101, I remember before buying a MBA I went to the apple store to test it.
I've been impressed by the boot time on some youtube videos and wanted to see that by my own, so I tried rebooting an apple store MBA and... It was REALLY slow, like +1minute for boot... Was on every test device, the apple store guy didn't understand either... Now I have a MBA and it boots in a few seconds.
So maybe some of the stuff they put in there slow down the demo devices, I don't really know!