Since my SSD-equipped, btrfs using laptop (Thinkpad X60s running Debian testing, kernel 3.2.15) boots from power on to graphical login in 27 seconds (13.5s of which is the time taken to get through the BIOS boot sequence) I suspect it's something specific to the parent poster's system.

I have btrfs (with lzo compression) on a rotating disk, and the boot feels a little slower (one or two minutes total?) for reasons I haven't really examined. I'll have to check if something messed with ureadahead.

It's a 2TB drive doing a full fsck each time, though I don't know why.