I think a good travel agent is worth their weight in gold. For a start if things go wrong instead of yourself sitting at the end of an 0871 number, being passed from pillar to post and clocking up £50 worth of phone costs in one session and a potential coronary, they do it for you. It's always worth giving them a chance to match a web price for this alone.
There are also many folk who are not like HT addicts who have neither the time nor the inclination to spend hours & hours on the net first researching & then trying to get the best price.
Year before last I went to Port Aventura with another family, my friend was so pleased with her travel agent who got them a second room in the hotel for only an extra £70 for the week.
I would have realised that her 13 and 15 year old were both being charged as adults, with just a small 3rd and 4th adult reduction in a (so called) family room, whereas she didn't. The travel agent pointed this out, booked two standard rooms, for the 70 quid & she was over the moon with all the extra space and privacy.
She thought her agent was brilliant and apparently they spent two hours going through various options with her.
The complexities of ABTA, ATOL, bed banks, package holidays, dynamic packages, what is and isn't covered by credit, debit, visa and Insurance seem better understood by good agents than lay people, so that's another plus to using them.
On the downside though because the money is so poor in the chain high street shops, you are likely to be confronted by somone on minimum wage who is 18 and can't actually afford a holiday themselves, so is unlikly to give top notch advice on complex itineries and destinations.
Doe