Vinyl
Standard construction sees layers of durable, weatherproof vinyl surrounding an inner core of foam insulation, although the cheapest models lack the foam core.  Lightweight and impervious to insects and rot, vinyl doors are durable players. Colors extend throughout the vinyl layers, so scratches don't show.

Unlike steel, vinyl is resistant to dings and errant baseballs; many types come with lifetime warranties. Despite their higher price, over the long run vinyl doors may be a more cost-effective option than steel.

Heads up: Polyvinylchloride (PVC) is considered environmentally unfriendly.

Insulating value: R-4 to R-12

Cost for a 16-by7-foot double door: $900-$1,500.