just get 18-55

Yes, but depends on OP's budget.

$$$ 
That's correct. But if I were a casual shooter wanting to take excellent macro shots but not willing to spend a lot, I would invest in something like the G12 or XZ-1.

Anyway, I doubt that the primary reason for the OP to get the D5100 is to shoot macro. I'm guessing he's more into general photography which is quite a norm for a person just starting out with a DSLR. In my opinion, when starting out, reach is more often a wanted feature than getting shorter MFD. If he is a serious macro shooter, just buy the body only and couple it with a 60mm f/2.8, 105mm f/2.8 VR or the 200mm f/4.

thats y i said depends on preference, im not implying he shud get 18-55 not 18-105
im jz saying that ppl shud not take for granted that the choice shud always be 18-105 over 18-55 

local D5100 kit lens is the 18-55...stick with it.
if u want it with the 18-105 u of cos have to buy D5100 body only and get a used 18-105 seperately, which imo would be a waste of money as ur probably paying about rm300-400 extra just for that slight reach.