for what concerns your initial question, Locale.
I've been using it everyday since months.
I've 4 settings:
OFFICE - triggered by the location (no gps)
-- puts the ringer volume to 0 + vibro
-- change the background to a nice "officish" bg
-- turns off GPS
-- puts brightness to Auto
-- put my gtalk status to available but "working"
-- screen timeout to 1 min
HOME - triggered by the location (no gps)
-- puts the ringer volume back to 50%
-- GPS OFF
-- gtalk status to available with no status message
-- brightness to 0%
-- screen timeout 1min
-- wallpaper to "homish" relaxing one
CAR DOCK - triggered when i put my droid in it's car dock (locale plugin)
-- brighness to 100%
-- GPS ON
-- Gtalk status to BUSY and message "driving"
-- ringer volume to 50%
-- screen timeout to "never"
-- launch "Grooveshark" (via locale plugin "shortcut" which let you launch any activity)
I bought my droid cause of this application. It's absolutely a MUST, in my opinion. The triggers work almost perfectly. I got used to the fact that the trigger based on location takes a few seconds to realize where you are. When i first started using this app I didn't like this at all, then i realized that the advantages of the automation overcomes this little issues you get.