Ubuntu 11.10 has broken the Startup-Manager, here are steps to make Windows always boot first
If you change boot order manually in /etc/default/grub or via startup-manager, you will discover that each time a new kernel is delivered, Windows is moved in another place in menu. You need to force grub to put Windows at top position each time it rebuild its configuration.
For this use the following commands:
cd /etc/grub.d
sudo mv 30_os-prober 09_os-prober
sudo update-grub
and reboot.
Older Notes:
Ubuntu has started using Grub2 and the menu.lst is now gone. Install the "Startup-Manager" to change default boot item.
It's installed under "System, Administration, Startup-Manager
Common Tasks, review and add here directly:
http://ubuntuforums.org/showthread.php?t=1302743