My own personal site at http://www.davesgonemental.com uses Caribou as its theme as of a week or so ago.
I use the geo-mashup plugin for the mapping, and Akismet but otherwise am pretty light on plugins as I find they can slow down a site far too much.
I didn't customise the theme at all, and decided that for my relatively simple needs the straightforward combination of red, black and grey were all I needed for colours when selecting them in the back-end. Turning off the menu bar seemed sensible because although I have quite a lot of content it could be quite easily categorised into just a few sections which fitted nicely along the tab bar. I used the footer for a subtle link to an About page.
Of course, I'm a complete theme tart - so there's no guarantee that if you read this in 2009 I'll be on the same theme! Caribou is going to spawn a lot of children in the coming year or two... Similarly, our new blogging theme due out this week is a delight, especially with its support for WP2.7 and threaded comments.