On the trainer i keep it at 90-ish... but when i'm on the road it tends to drop... I try to keep it at 70-80 on the flats, 60-70 on hills (sometimes drops to 50... oops!). the guy that did my bike fit at the LBS looked at my knees and said "Some people spin in easy gears, some people mash in hard ones. Looks like you're a masher"... i wondered how he could tell!
on hills, i concentrate on pulling up rather than pushing down, and that seems to help keep the cadence up (i'm still pretty new to clipless, so "pulling up" is still novel to me ). Someone told me that your calfs/hamstrings are your "climbing muscles"... is that right?

<--- just had to grin, dunno why... it's the whole talking about bikes thing. i've been in a "bike mood" the past few weeks (ie: i NEED to be out on my BIKE!!! too bad they don't have a "crazy" smiley. that would fit right here )