Brian Baird wrote:
...and bought a vertical grip for the 10D on eBay. I've got a couple
extra batteries coming in from Thomas Distributing so I'll have a
total of 4.

I shall never run out of juice in the middle of taking photos again!

You'll get spoiled
I've loaded up my DSLR (Pentax *istD) with litium CR-V3 batteries including
the optional grip (equivalent of 8 AA batteries). 1500+ flicks later and the
meter still shows a full charge.
No doubt I'll forget about it until the batteries fail in the middle of a
shoot.. . like the propane tank going empty in the middle of a BBQ