[8D]Gas- fuel relatively cheap, easy to tune, relatively reliable idle, but generally are for planes in 10 pound and up 6 foot wingspan and up range. Initial cost relatively high due to large size.

Glow (Nitro) - Initial cost relatively low, fuel cost high, available for all sizes but the very small "parkflyers", messy due to oil content of fuel, noisy, relatively hard to tune especially for idle.

Electric- reliable operation, low noise level, low cost of energy per flight, but very expensive in up-front cost for motor, batteries, and charging equipment.

Since I like smaller sized planes 3 to 6 foot wingspan I would use electric for small planes and glow for medium sized planes if I were starting out now. I might consider electric for medium sized planes. Gas is only way to go for the big birds, but they are out of my league both in cost and skill level required.