I'm a wee bit fond of AWStats in relation to what's available out there.
But I was wondering what others find useful. Freeware/opensource stats tracking software such as AWStats, WebTrends and what not.

What is it out there that you guys use and find worth recommending?

That would return vital stats, among others, such as:

Referring URLs
SE keywords/keyphrases
Visits/Hits/Pages
Errors received
Bandwidth usage
Daily/Weekly/Monthy breakdowns

and so on.