Choosing events/specialties

I'm curious how people go about deciding which events they will train for and enter in meets. Do people pick events they enjoy swimming or events they do well at or events they think they can improve at or...? Is there any way to determine which events you are likely to be best at? I've always thought of myself as a distance person, mostly because I've never been particularly fast, but as my technique improves I seem to be getting faster in the shorter distances more than the longer distances, even though I am training for distance! After doing some timed sprints this week my coach told me he thought he could reduce my 50fr time by 3-5 seconds if I wanted to train for that. Naturally that idea appeals to me but I had never considered concentrating on free sprints before. There seem to be several ways I could go that look promising and I'm not sure what to concentrate on, or even on what basis to choose! I'm also curious to what extent people train specifically for their specialty events. A lot of the people in our club only swim during the club workouts and so don't really tailor their training for specific events, at least to the extent that those of us who also train on our own have the opportunity to do.