My thoughts on a "good" cache -
Right now, as a beginner and mom to twin baby boys, there can't be too many 1/1 caches in my home area. Considering the baby stroller, the more accessible the better. Even when I don't have the babies I'm on limited time. So a "thank you" to the placers of all those 1/1's!
Also, alot of these caches show me a park or area I haven't seen before, and I think that's neat.
There's over a thousand caches in my area, so there's probably a range from crappy to ultra-nifty. They're all a reason to get out and play!