Today booting into Intrepid and 2.6.27 (not updated for a couple of days) the boot progress bar stopped at about 15% and I eventually hit Ctrl-Alt-Del and it jumped immediately to about 80% and then X failed, and dropped to a console login which also failed to work. After a few more Ctrl-Alt-Del's I booted into 2.6.24 and everything booted normally. Suggest upgraders keep their 2.6.24 Hardy kernels for a while just in case. Wish I had more technical info on the exact problem but had no time and I can't get to that machine right now.