I always think of the car rental as a kind of treat for myself. I rent something that I would like to drive everyday (but can't afford to at home). We have a midsize (Pontiac G6) as our family car at home so I try to rent something different when we are on vacation and have a little fun with it. I like to rent a full size with
Alamo, then you get to pick from the aisle. Sometimes we take a sedan (Charger, Impala, Mazda 6, Camry), sometimes they have SUVs or Crossovers in the aisle, occasionally some premium vehicles like Infiniti. If I'm in the mood for something sporty (and the prices are reasonable), we'll rent a convertible (usually Mustang or Camaro lately).
Gas prices are low right now so why cram everyone into an econo-box to save a few dollars on fuel.
Live a little and rent something that you will enjoy driving!