Not a recommendation, as I haven’t used it yet, but a really cool idea that I will be playing with in the coming weeks. Loggly is a cloud-based log file analysis tool. It pulls the logs you want into the cloud and allows you to analyse them either through RESTful API calls, or through a cool-looking shell-like interface. Very useful for both ad hoc investigations (without giving everyone access to a secured server farm) or for integration into Admin reporting systems through the RESTful API.
Click here to visit their site.