If you book your own travel several new meta search engines have recently come online which can help you find that low fare or last minute hotel deal you've been looking for.
I stopped using a travel agent about 5 years ago and while it can take a little time to find that deal you want, with a little work it can be done. Aside from going directly to the airline web sites looking for fares I also compare fares using Travelocity and Expedia. But three new meta search engines have emerged that offer another avenue to help you. They are Kayak, Mobissimo and Sidestep.
To test these new services I did several searches for travel I have planned in the near future. The results were interesting. To start Travelocity and Expedia results were almost identical with Expedia being just a bit cheaper. However the three new search engines all found cheaper options than Travelocity or Expedia and not just by a few dollars but by a substantial amount with Kayak consitently finding the cheapest fares.
Based on these results I would suggest that if you have the time, that it is worth exploring all the options available to you when booking a trip. While one service might find a cheaper flight another might offer a better itinerary. So it all depends on your needs.