Yep,
You will definitely love DCC. When I picked up my Digitrax Zephyr (got it slightly used from the LHS off the store layout as a display model
) I was amazed at how much better my DC loco's ran with it.
And when I installed my first decoder (an MRC AD370 sound decoder) I was hooked for good. The ability that DCC gives you to configure how your engines run is well worth the cost of the initial investment of the DCC system.
BTW if you are looking for DCC sound on the cheap look into the sound decoders MRC offers. While they are generic in sounds they are good decoders and the sound adds a lot to things.