I use number 5, after Mansell's famous "Red 5" and also its success in Formula 1, its won quite a few championships..
32,
Not my age or birthdate, but the squadron number for a USAFE fighter squadron that used to be based near my home town from the 50`s up till `94.
Spend a lot of time photographing, visiting the base on 4th of July and such, so that number has a special meaning for me.
Hence i almost always pick it (beats picking a birthyear or age)
32, no real reason apart from it's my favourite number.