The strange thing is that the kind of anatomy that you take in College might be better than the anatomy you take in medical school. In College, there is more time to get into some the small details.
The argument against not taking anatomy before medical school is that is will be redundant for the most part and that you should take other courses now when you still can.
The argument for it is that anatomy experience will make anatomy in medical school easier and let you get that nice 'A' that you can leverage while going for competitive residencies.
I held the 'against' argument pretty strongly for a while, but then I got a little beat up in anatomy, so I'm not so sure anymore.
If taking anatomy over the summer sounds fun to you, go ahead and do it. I can only help and most certainly will not hurt.