I have been looking at the "_layouts/SpUsageSite.aspx" logs for my site, but they are giving erroneous results (eg 0 unique visitors when I know at least I have been on the site)
What is the best way to see these logs in a better way than the ootb functionality?
Did you enable the usage processing and the usage logging for the site in question?
You can enable them in you central admin under: Operations -> Usage analysis processing
It may also be that the processing is limited to a speciffic timespan
I have come across a bug with the Usage analysis processing to do with UTC date conversion which resulted in the processed numbers being erroneous. This is apparently fixed in SP2, but we have not been able to implement this quite yet.
The alternative is a bit onerous as you need to copy the usage logs from each front end server to a location and configure the log parser to store the information in a data base. Serge van den Oever steps through this quite well here. I don't really recommend this as a regular process as it takes a lot of effort, but it does give you a huge amount of information for when you wish to take a detailed look at usage on a particular point of your SharePoint farm.
Ideally we would have a solution to parse the logs automagically using the log parser utility and provide that information in SSRS reports.