[sf-perl] Favorite form validation modules?

[Fred Moyer]

I've been using Data::FormValidator for a few years now and think it
is the best thing since sliced bread (not that I don't like slicing my
own bread that is).

It is nice because it's simple, comes with a number of existing
constraints, and also is easy to integrate with existing systems.

I'm interested in hearing what others are using for form validation.