I'm running (or rather trying to run!) SL on my Mac, specs as below and was wandering seeing as my mac is a pretty standard config what settings i should set to be able to get a good experience. At the moment things are woeful enough that i'm not going to give it too much longer before just throwing the towel in! Things are jerky, blocky and well, just slow

I'm running:
20" Intel iMac (the original one with the 2Ghz Core Duo chip)
250GB HDD with over 118GB free
2GB ram (fully loaded)
256MB Video Card (i think it's the X1600 in these?) again, fully loaded
2Mbit broadand using wireless although i've tried wire and it doesn't make much difference
I see the right hand meter going up quite a lot but the lag one barely ever.
I'm running windowed but maximised to full width (maybe i should go fullscreen? doesn't make too much difference i don't think). I have two monitors. Maybe i should use just one?
I thought this was pretty well tricked out (so to speak!) it FLIES with everything else i throw at it yet this is painful really!!
Thanks for any help.
Oh, i should mention that one of the cpu cores is permanently up near max more or less.
Martin.