I'm trying to decide between the Nikon d5100 and the d90. I know the d5100 doesn't have the AF motor in the body where as the d90 does. What are the advantages to the AF motor in the body? Also what macro lens would be good with these two particular cameras? This will be my first DSLR and I have been researching for a few months now, but I just need some help from some of the more experienced photographers on here. Thanks.