bingo. my fave combination.
there's one major upside to server logs though:
reporting all requests and traffic for all files
... for you can't put urchin code into an image
And won't notice access to areas you didn't use js tracking on.
hotlinking / download trends, media files, security issues... unless you serve every single request through jump pages, you won't know what takes up MOST of your data traffic for some sites. And even then you might not notice accesses or break-in attempts to sections you thought to be safe.
So I'd rather say that your agent log is complete fiction...
...traffic reports are not.
ugh... could they be any more real