I have just purchased a DCC system, it is not up and running yet but will be very soon. I believe you have to ask yourself several questions to see what sort of system suits you best.
1 cost.
2 power requirements, can the system supply the power you need to run the number of locos you want.
3 controller style, base only, base w/ handhelds, tethered handhelds only, infra red, etc.
4 2 or 4 digit addressing
5 # of functions controlled
6 easy to program locos
7 easy to operate
8 sound
and on and on and on and on and..........................
Only you know what your needs are, determine those first so you know what you are looking for. Many people will tell you what system to get based on what they like, but that may not be what is best for you.
I bought the MRC Prodigy, most people bash it, but it had all I needed and was affordable.
Check out Tonys train exchange and Loys Toys online, tons of info to be getting on with, as far as new layout wiring info check out Alan Gartner's wiring for DCC.
here's the links:
http://www.ttx-dcc.com/
http://www.loystoys.com/
http://www.wiringfordcc.com/
Good luck, don't rush it.