I wouldn't recommend using a generic travel agent. They just don't generally know about Disney. The one we used for our first trip (we just booked flights through them, and only because we had a voucher) not only tried to rip us off with the flights, but also tried to tell us that we would need to pay extra for a 'night pass' to see the fireworks etc. They may have been getting confused with the seasonal hard ticket events, but that's the kind of stuff that's very easy to find out on the internet and they should know.
The only time I would bother with a travel agent again would be for a WDW trip, just because I could get them to make all my ADRs and not have to panic about being online or on the phone to book as soon as my window opened up etc. I'd probably go through one of the US Disney specialists just for that land only portion of the trip.
Having said that, for this trip I bought the 10 day passes through an Australian Disney specialist TA (only because I couldn't buy them direct and I certainly wasn't willing to give Flight Centre my business), and was very happy with the service I got.