Thanks for all the advice - I'll put them on one circuit and on two
dimmer switches (more flexibility in the one big room [40x20] ). Now I
just need to figure out how to run that circuit so that one switch
doesn't effect the other set of lights. (Before I scare anyone, I am
relatively new at the electrical stuff - but I do get a cert.
electrician to come in and check over everything and then attach my
circuits into the panel...I'm still wary of the panel....). Can the
power source just come into one dimmer (which goes out to its lights)
and then onto the next dimmer for the next set of lights? I'll have
to get out my sketch pad and try and figure it out...

Thanks for the quick & helpful responses!