The 105 is a great lens, but a bit more difficult to shoot, and is more limited in subjects.
But some of those subjects can be real winners. Witness:
http://www.ncups.org/sea/SEA2009/california/index.html
My GF, Adm. Linda, took that with a 105 on a D40. I saw the
ling with his mouth open way back in a crack, and figured some
sort of cleaning behavior was going on. I had a 50mm on a
fullframe sensor (Nikonos RS (film)) and knew I couldn't get get
the shot because he was so far away, so I pointed him out to
Adm. Linda, and got out of the way. She's like to win a tropical
trip for that shot which got 1st place in the Underwater California
category of the Northern California Underwater Photographic
Society's SEA 2009 International Photo Competition.
The 105 would be cool for shooting shy subjects (say, clownfish)
That said, she's mostly shooting the 60 mm these days. When
she got the housing, the only AF-S macro was the 105, and the
D40 requires an AF-S lens to AF. And if I were to only have one,
it would be the 60 mm.