I wish people would post what macbook they have (quite a few left that out).
Mine's a 2010 13" MBP, about 5 months old (least the battery is).
92% health
13 cycles
Current Capacity: 5359
Original Capacity: 5770 (I noticed some one else with the same MBP had a battery that had 5785).
Anyways, seems a trend (From what I can tell) for the 2010 13" MBP's to be in their low 90's (Where as my original Macbook, mid 2007 model last I checked has 97% battery health. And I noticed some one else with same age mac also had a pretty high battery health, higher than my MBP. They claim these batteries last longer but they seem to lose a lot of initial charge right from the start judging from this thread).
Oh, and for both computers I do leave it plugged in most the time (maybe once or twice a week they get discharged. The other one to 35% but because of longer battery health this one usually to 65% or 55%. Most of hte time I use it like a desktop).