RAM Usage on MBP C2D Very High

[hardhead89]

Hey,
I have a MBP 17" that I got about 16 months ago. The machine has been great so far. Recently I have been noticing that the amount of RAM being used by the system is rising. I have the standard 2 GB that it came with by the way. When running Safari, iTunes, iChat and Mail I usually only have 80 MB free according to Activity Monitor. Is this normal for this machine? I also see a ton of other things running inside Activity Monitor which I assume are system scripts.
Can anyone let me know if this is normal or not.
Thanks

 

[deadpixels]

maybe a new app you installed that is leaking memory? install and run onyx, run all the cache cleaning stuff, cron scripts ++ it's worth a try.

 

[hardhead89]

Thanks!
That worked like a charm.
How often should I run Onyx?