Nikon D5100: Brand new ($600) vs Refurbished ($500)?

What's better?

how fast do prices decrease anyway, should i wait?

Other than the $100 difference and a 90 day warranty vs a one year warranty, as long as the camera was refurbished by the maker of the camera, there's NO difference

Wait for what?

Lots of people have very good luck with refurbished gear as long as the refurbish was done by the camera maker and not some fly by night outfit claiming they know how to perform such work.

If the refurbishing was done in the factory, grab it. If not, get brand new.

Don't wait. If you have the money, buy now. Think of all the photo opportunities you'll miss if you delay.

http://keerok-photography.blogspot.com/2012/09/first-time-dslr-buyers-biggest-mistakes.html

Prices do decrease but they decrease fastest on new cameras. The D5100 has been around for a while so is less likely to decrease rapidly again any time soon.

If the D5200 replacement gets launched that will push D5100 prices down, but as it hasn't been announced in the autumn photo shows, it seems unlikely that there will be one this year, as they like to announce and get new models out before the Christmas buying season.

The other thing which affects camera prices, both up and down, is the strength of the dollar vs the yen. And if you can accurately predict that you'll make lots of money over time and won't have to worry about the odd $100!

So no, don't wait. If it has been refurbished by Nikon, go for it.