I have seldom had a travel agent whose fares I couldn't reduce by knowing more about the fare rules than they did. A number of times I've had difficulty getting things booked the way I want because the travel agent made (incorrect) assumptions based on not understanding the fare rules. Then there are all those times when travel agents entered frequent flyer number incorrectly (or not at all), causing me even more work.

Travel agents are great for the person who flies once per year and has no idea what to do, or someone who values their time far higher than the money they'll lose using one. For those of us who have any clue, travel agents are, mostly, a waste of money.

The one exception for me is that most online systems will not discount RTW fares, or even allow them to be booked. This pretty much forces you to use an airline directly, at full published price, or find a travel agent who'll do it cheaper.