As a travel journalist, I want to tell you how much cash you can save by doing this on your own! Even websites like Travelocity and Expedia charge a little extra for services.
To do it on your own, my advice would be to locate the deal (for example, a good price on flights from Delta listed on Expedia) and then go to the airlines/hotels/who-evers website and find the deal there- minus surcharges.
However, if you don't want to take the time to do a lil research, a company is a great way to go. I've heard good things about KK, but I've used Small World Vacations and loved them. My agent got me an impossible dinner reservation, and changed plans for me at the last possible minute.