As long as you are replacing the water heater, you may want to consider a short fat style. My next water heater is going to be of that variety with an overflow pan mounted on a solid table which will be screwed to the basement floor. Just be sure the pressure valve tubing runs down to within inches of the floor so that in the event of pressure release you don't get sprayed by hot water bouncing off the drip pan or table.

My next high efficiency furnace will be one of the short compact Rheems mounted on a steel table which will be screwed to the basement floor. This will make filter changing, blower motor oiling, and general yearly testing and cleaning easier. Mounted higher also keeps it farther away from the humid basement floor.

Bountyhunter