While Functional Programming in Scala is great, it focuses on areas of Scala that I think are better tackled once you're more familiar with the core language - pattern matching, traits, case classes, variance, for comprehensions...

I find that the best book if you want a deep understanding of the language is Odersky's Programming in Scala. Complete, thorough, well written. It does expect you to have some programming experience, and some bits are perhaps over-detailed, but as long as you allow yourself to skip the bits that bore you, you're in for a treat.