When I installed 11.04 I had the same problem.

A few other charastics, may be he didn't mention. During the boot up, when
the dual-boot menu usually appears, a message from the 24" ACER monitor
complained about a non-supported signal was being feed to it. After what
seemed like a longer than normal the Ubuntu desktop-boot-up screen appeared,
then there was 11.04. An FDISK or GParted showed that a Windows partition
was still there.

After a lot of pain-in-the-ass backing up Ubuntu and Windows files, the only
way I found to correct the like of dual-booting was a complete reinstall of
Windows and Ubuntu.

I do have good backups now and great documentation of all modifications and
software installs made on both OSs.

Chris, I tried the GRUB_TIMEOUT=0. Just like you said, no dual-boot menu,
straight to 10.10. Currently I'm using 10.10 because I could not figure out
how to get 11.04 to dual-boot. Then when I changed it back to
GRUB_TIMEOUT=10 and a 10 second dual-boot menu came up.