What kind of cage is best?

Wire cages provide better ventilation than aquaria, provide Junglegym exercise, are easier to clean, and are easier to attach bottles and wheels. Best to keep the cages out of drafty places in the first place, but if you can't, protect from drafts by enclosing 2 sides and top at a corner in cardboard. Note that 1/2x1 in. welded wire fabric floors can catch and break a rear leg. Floors should be finer or coarser, or set onto shavings. Hairless rats, and mothers with babies are safer in an aquarium. 5-gallon takes maximum one adult rat. 10-gallon, two adults.
Wire cages can be a problem with young rats who might get their legs caught in the mesh and injure themselves. Ventilation for aquariums can be helped by placing small fans over them to increase air-flow. Wire bottoms on cages have been known to cause bumblefoot in some rats, though the swollen foot may be from injury from getting a foot caught, though more often bumblefoot is caused by infection. It is however, easier for a rat to injure there feet by catching them in the wire floors and breaking or spraining feet or legs even.
Aquariums are easier to clean, often less expensive then cages and often safer for young rats who sometimes will get a leg caught in the wire of a wire cage and injure themselves, sometimes so badly that they have to be put out of their misery. (a compound fracture in a young rat is expensive very hard to treat, thus its often more kind to put them down rather then induce further pain on them.)