Although the Event Viewer UI in Windows Server 2003 lets you set the maximum size of an event log as 4 GB, in actual fact you should generally never exceed 300 MB for this setting.

There are several reasons for this recommendation.

1. Event Viewer wasn't designed to scale well for very large event log sizes.
   
2. Setting the maximum size too large could lead to missing events or even corruption of the event log.

For more information on configuring maximum event log size, see http://technet2.microsoft.com/WindowsServer/en/library/5a86ab0f-c7eb-45ed-9e5e-514173bf15e31033.mspx?mfr=true.