SaschArt easyLimiter

easyLimiter is a simple lookahead limiter optimized for performance and ease of use. The plugin is quite transparent, even when pushed towards somewhat more extreme settings. It works best for quick limiting tasks, though, when used on individual tracks, or on a less busy bus and master channels.
Extremely lightweight in terms of CPU consumption, which seems to be one of the SaschArt’s priorities while developing his plugins (and rightfully so). This is particularly important when it comes to the limiter plugin, as it is one of the most CPU friendly limiters currently available. 

http://vst.saschart.com/