Have you ever asked your self this question?
With the proliferation of websites offering hotel rooms and more so websites that suggest itineraries for "do-it-yourself" vacations, there is much reason for you to think harder which direction to choose.
Traveling on your own is a very enriching experience. Researching the destination and booking your own hotel/ resort would make it personalized and more "within your control". Your own preferences to a T would be followed and you "save" on money because you did it all by yourself without the help of an agency.
If you did your research well, you may be able to go to unbeaten paths that tourist buses may not cover. You would have more time and more intimate connection to your destination because of all the things you'd learn along the way.
Yes, the following statement would come from me, your travel agent - It is much more enriching to go to do-it-yourself vacations.
Having said that, why is it not for every body?
For many reasons.
One because not everybody would have the time to plan out several days itinerary. More so if the destination is unfamiliar and quite distant. Quality research would save you time. Haphazard research on your destination would imply more spending to correct your steps.
Second is experience. Although this is something you'd like to earn in the trip, it pays to learn from others so as to maximize time and minimize mistakes along the way. Hear your travel agent out and let her walk you through the trip even before you step on that foreign land.
Third is because of documentations that may be required for your trip. I for one do not like reading long statements from application forms, waiting in line or waiting to be attended to in a phone call that lasts forever. Your travel agent can do the dirty work for you and assist you in visa processing, scheduling and documentation.
In summary, you could choose either way. It all depends on where you are going and how ready you are to personally attend to the details of your trip. An off the rack travel package may just give you a chance to go on a whim. A do it yourself travel may give you a chance to teach others how to get there next time...without the glitches. :)