There are several benefits to using a changing table. For starters, you'll be able to diaper your little one at a comfortable level--most are 36 to 44 inches high--and you'll have diapers and other supplies within easy reach.
Changing tables have shelves, baskets, and/or drawers you can use to store essentials like wipes, rash ointment, and a toy or two to keep your baby busy. You won't have this handy storage if you change your baby on the floor or in a crib. Changing tables usually include a vinyl changing pad. Washable cotton and terry-cloth covers are sold separately and come in a variety of colors and patterns.
We think that if you're not going to change your baby's diaper on the floor, a dedicated changing table with barriers on all four sides and a safety strap is the safest way to go.
Two examples with rails are the Badger Basket Baby Changing Table with Six Baskets and the Glenwood Changing Table from Delta Children's Products. (We have not tested changing tables.)
The second-best option is a removable changing pad that can be secured on top of a regular dresser. If you decide to go that route, which is the least expensive option (they're about $23 to $60), look for one with at least two contoured sides that have a baby-restraint strap and a way to attach the pad to your dresser top, and nonskid backing. But to be as safe as possible, we recommend buying a pad that lets you attach it to your dresser, such as the 4-Sided Change Pad by Basic Comfort, which has a strap for baby plus a "security strap" on the bottom of the pad that you can screw to the back of your dresser.
If you want to go green, you can also find pricier pads made with organic cotton, such as the Better Basics Organic Cotton Contoured Changing Pad by Naturepedic ($99). It features a safety buckle to keep a squirming baby in place and "easy-snap screws" to keep it firmly attached to your dresser or changing table.
The reality is that some babies hate having their diaper changed and will actively resist it, especially when they're older. If your child belongs in that camp, you may find it's easier--and safer--to simply change him on a pad on the floor. A bed is fine, too. Either way, you always want to keep a hand on him in the process, and if you're using a changing pad, always use the security belt. Never step away from your baby, even to grab a diaper. He'll probably be too big for a changing table when he's about 2 years old.