Post review updates:
Switched to CyanogenMod 7 nightlies, so am now running Android 2.3.2
Observation: if you install CM7, and then install the wrong version of Google Apps, your phone reboots over and over until you roll back to CM6 (which involves a full device wipe, so most annoying), and then roll forward installing the correct Google Apps at the same time. I paid the price of a pint to get the ROM Manager Premium, which makes avoiding this unfortunate scenario very simple indeed.
Other handy installs:
Compass
Bubble Level
ClockSync (my N1 doesn't sync with the phone network)
My Tracks (for when I'm tramping about in the woods avec les chiens)