I like variety and spontaneity in my life so, in the past, I've used all sorts of film. As I've been using film since the early 1970s, I've found a few favourites - but I've never deliberately limited myself to any in particular (aside from when I shot weddings as a part-time income supplement).
However, now I'm a bit older and have a couple of ambitions to achieve, I feel I need to concentrate my shooting to a few films - primarily to ensure I get consistent results and get the best out of the films.
I've been particularly impressed with Ilford XP2 Super and I've got about 20 rolls of 120 in the fridge. However, I'm currently using up my last few rolls of 120 Tri-X. For colour, I love Kodak Portra 400 as it has a very natural / neutral palette and, like XP2, dries pretty flat (a major advantage as I scan my negs using an Epson V750 flat-bed).
If I want to go a bit off-piste, I'm partial to a bit of Velvia 100 but, as it's a transparency film, you only get one shot at exposure and it can be very contrasty - so I only shoot that film a few times a year and usually on cloudy-bright days.
There's nothing wrong in trying a bit of everything but, at least for now, I'm deliberately limiting my options.