I tested the 105 DC and loved it, but ultimately wound up with the 135 DC because I already had a Leica 100mm APO that I could use at/around 100mm. My input would be that the choice depends on the desired subject. If you are looking for a portrait lens, definitely get the 105 DC -- it is tailor made for that sort of work, and it has a lovely character, the DC function is subtle, but can improve backgrounds and foregrounds if necessary. It can also act as a variable soft-focus lens if necessary. Finally, in general use it is very sharp, has a fast f/2 aperature, and auto-focus. It is an excellent all around lens. One copy I tried had difficult focusing on the D3 though, so be sure you check that carefully. The 105 DC also is a really good lens to go for if you are looking to play with shallow depth of field -- the look of the lens is gorgeous, so if you shoot wide open a lot, it is the way to go.
If you are just looking for a sharp, general purpose 105mm lens, get the 105 VR -- the VR will help you handhold, and it is probably a sharper lens corner to corner (I have not compared the two though), it will focus closer and it uses AFS.
