Railfan,
While I'm a huge proponent of NCE I'd advise noting what others are using your area if you plan on running on other layouts or having guests run on your layout. Again I'm an NCE user and am very happy with the system. The products are top notch and the customer service is great.
Does anyone know the kind of plug Roco uses? I found this site that is selling stuff at good prices - djunction.com . They have a number of DCC ready Roco locomotives along with other European stuff.