You might want to spend some time reading at Tony's Train Exchange
http://www.tonystrains.com/
or at Litchfield Station
http://litchfieldstation.com/DCC-University/index.htm
Both are excellent places to buy DCC stuff and to learn about what's available.
To specifically answer your question:
QSI Quantum Revolution can be purchased with a MP15 sound scheme with a few different horns. The Programmer is NOT mandatory. If you ever get into sound big time and start to get a fleet of decoders, it might be helpful.
In case you haven't seen or heard a QSI decoder:
http://www.youtube.com/watch?v=KhHpRGTLI0s
It's factory sound, but the Revolution sounds the same.
Soundtraxx Tsunami Diesel can be purchased with 2nd generation EMD prime mover sound. It also has a bunch of horns to choose from. No programmer required, you set it up using CVs like any other decoder.
Both of the above decoders have sound, light and motor control.
In addition, you can find some "cheaper" solutions.
Soundtraxx (not Digitrax) makes the DSD-100LC and 101LC. Those cost between $50 - $60. They are also sound, lights and motor. They can be purchased 2nd gen EMD. However, the motor control is very old technology and quite honestly isn't very good.
Soundtraxx also makes a DSX series (sound ONLY), but programming a loco with two seperate decoders is not that easy. I have an Alco RS3. It runs and sounds good, but too hard to set up.
http://www.youtube.com/watch?v=vPwtfI0VASg&feature=channel_page
Digitrax has some sound available, but if you don't buy their Programmer, you are pretty much stuck with what comes on the decoder.
Loksound is another option. Expensive, around $110 and uses 100 ohm speakers which are hard to find. Lots of people say they have excellent motor control and sound. I have not tried one. Don't care to get involved with the 100 speakers.
If you buy WITH sound installed, lots of mfgs use QSI. BLI used to, now they use their own. If you are considering Blueline, read up first. Lots of people seem to like them, others say they are a bear to program after adding the DCC decoder.
I have actually purchased Atlas diesels with sound for less than I cold buy the one without sound and add my own. Just depends on how hard you look.
Athearn has chose to put MRC decoders in their sound locos. I have none and based on what I have read, I will have none. Do a lot of research before you even consider MRC. I have seen many, many unhappy people with MRC decoders. Apparently they sometimes work, sometimes program and with luck work for a while.