Up until now I've been using AWStats on the server, but I was trying to secure things a bit more and wanted to reduce the attack surface - having examined my logs and seen a few interesting requests being targetted at the cgi-bin perl.
Anyway, on my travels I found WhosOn, and I just had to buy it. Its chugging away on my pc as we speak, making wonderful gurgling noises every time I get a visitor / dubious request etc. Its quite addictive viewing :)
Go on, go buy it, you can become a stat bore at parties too ;)
Don't let the fact that I bought it stop you from telling me why I should have bought product X, cos it's bigger / better / faster etc - but be aware, I know who you are, and I'm probably watching!!!