I tend to drive into parking spaces. Reversing is to be avoided - especially when parallel parking as you have to look at the road behind you and concentrate on the parking. There is actually a remarkably high degree of skill required to park within a decent distance of the kerb but not have to make several small manoeuvres to get there.
Driving into a space at the side of the road, if there are other cars there, is virtually impossible as you dont get the precise movement ability you get when reversing in.