Hey, colour has a u in it.
mostly just so that I can use j/k to navigate around
Quickly check my published calendars (also see this: exchange to ics).
Mostly so that I can see what SpamAssassin (personal) or PureMessage (work) has thought of the email.
The major time saver for me these days, rapid filing of email, works well across IMAP accounts.
I was having various problems with GMailUI & Keyconfig not playing together properly, but Nostalgy has largely removed my need for keyconfig, as the rapid filing using Nostalgy’s Save function is great.