I use perl every day and awk almost every day. Awk is useful for commands where it forms a small part of an overall pipeline and needs to be somewhat terse, and yet fast. Gawk is actually fairly fast, mawk[1] even more so.
Well, there are languages I learn to improve my mind, and to improve my craft. As far as the mind goes, perl is nothing new (on the mind to-learn list: Haskell, OCaml, Eiffel, Erlang). Craftwise, it looks very useful.