If you are looking for a syslog solution there are a number of good syslog devices.
Log Logic is really nice and is an appliance and you can also get a 2T storage with it.
However, if you want to just have something correlate the logs for you and see the events that are possible issues. Check out CS-MARS.
It is actually better to use both solutions though. Store your logs on a syslog server and have CS-MARS correlate the events and show you what are possible threats.