Dominus has a very nice article/talk on the subject of strong typing and Perl, which argues that strong typing is a good thing when automatic type inference is available. He gives some lovely examples of the power of ML-style strong typing.

If your dislike of strong typing is based on languages like C and Pascal, it's well worth checking out a modern system such as O'Caml - which incidentally has a compiler that produces exceedingly efficient code, rivalling C.

Sadly, Dominus concludes that adding this kind of type system to Perl would be like trying to "make a hot fudge sundae with mashed potatoes instead of ice cream".