I'm a lover of Piwik; switch out of GA for Piwik across all the domains I operate for myself and for some clients. One install can handle multiple domains/site/accounts/groups

Many of the clients appreciate the increased "privacy". And for applications (internal/public/private) it just makes more sense to me than GA.

My favourite part is that it's doing server-side log analysis for my traffic - not using those JS based widgets.

It's got event tracking (sweet) if you choose to use a JS based tickler to do that kind of thing.

Here's a quick and dirty doc I made about it: http://praxis.edoceo.com/howto/piwik