Whether you use a dynamically or, like Scala, a statically typed language you cannot help but ask yourself why people are attracted to the other one. Earlier this month Bill Venners wrote "Getting Dynamic productivity in a Static Language" [1], an article on just this topic, and invited opinions from other programmers with experience of languages using both type systems. You may enjoy reading the article and the associated comments that go some way to identifying the problem domains best suited to each. If you are still trying to decide which language to learn next this could help clarify one of the choice criteria.
Links:
[1] http://www.artima.com/forums/flat.jsp?forum=106&thread=253855