In my other RAID1s I've had /boot in the RAID.  Actually, there was no 
separate /boot partition, it was just in / and that seemed to work.  Now 
that I have a larger HDD, > 2TB, and I have to use GPT instead of DOS, 
I've had to make /boot partitions on both physical drives in the RAID1, 
but the two /boot partitions are not in the RAID.  When I had Ubuntu 
install grub, it installed it on both /dev/sda and /dev/sdb, which is 
where the two /boot partitions are found.

The thing that concerns me is that I don't see /boot if I run df, and I'm 
not sure how kernel upgrades will be handled.  Will they go to the hidden 
/boot partitions on both /dev/sda and /dev/sdb?  Ubuntu was clearly aware 
of them and I told the install that I wanted to be able to boot even with 
a degraded drive, so it was supposed to install the boot loader on both 
physical drives (and it seemed to do that).

What do you think?

Thanks again for answering so many of my questions!

Mike