I like the 1/48 the best. But I’ve been trying to branch out to 1/32.
Generally speaking, I like to buy the biggest scale possible since I enjoy building as large of a plane as possible. But not a lot of aircraft are built in 1/32 and when they are, they always seem to be really expensive. The only expensive 1/32 I have is the Academy F/A-18 but that’s because it got such great reviews. The Testors 1/32 F-117 Nighthawk I bought was like $27… I wish more 1/32 were reasonable like that.
Overall, I voted for 1/48 since that seems to be a good combination between a large size and reasonable price that won’t break my pocketbook.
The bigger the better as my eyes and fingers seem to get in the way with the smaller scales regardless of the type of model.