Have you repaired disk permissions with Disk Utility?
yes.
Do you ever leave your Mac on overnight to let it perform it's daily/weekly/monthly maintenance tasks?
I leave my mac on a lot.
If you've not restarted your Mac in a long time, do so.
I restart randomly.
Is your hard drive nearly full (This will impact on performance)?
It is basically brand new just got my mac like month and a half ago, 250gig hd, only have 40gigs on it.
How much stuff have you got on your desktop (Having lots of files on the desktop will slow your Mac down)?
0 files.
How many Apps do you have running at once (Are you closing them properly?)
Usually like firefox, ichat, itunes, ipages, stickies, ical.
I think its the ram, **** freezes sometimes.