Piwik looks interesting. I'm playing with the demo right now. It does look like they support goals[1]. I can't know for sure how effective it is but I will concede that log analytics is more powerful than I believed.

[1]: http://piwik.org/docs/tracking-goals-web-analytics/

For anyone who wants to play with the demo: http://demo-log-analytics.piwik.org/index.php?module=CoreHom...