Wow, I didn't expect to receive a reply from you! Thanks, I'll check out the Coursera course. I did start reading "Functional Programming in Scala" by Paul Chiusano and Rúnar Bjarnason, but wanted something a bit more beginner-friendly. Then again I was recovering from a concussion at the time, so perhaps I should revisit it now. :)
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.
I would definitely recommend Martin's Coursera course, it's incredibly well structured and very well delivered, with enough difficulty to be challenging but it guides you through very gently. Well worth it for learning both Scala and Functional Programming.
In retrospect I found it to be more of a "functional programming which happens to be using scala" class and less an "intro to scala". That's not a bad thing (nor a good thing, it's just a thing) but it's not necessarily what is most useful for a person.
A few years ago I joined a group which had been using scala for a while (since '09ish IIRC) and I took the coursera class to get up to speed. It definitely helped but the reality was that their code base was closer to being java++ than to haskell and a lot of the early habits I picked up from the coursera class were immediately beaten out of me once I got rolling there.
One could argue that they were in the wrong, but I disagree - Scala is a multi-paradigm language and not everyone is going the FP route (I recently heard Venners refer to Scala as a "reform movement for OO, which is how I personally treat it, but that's neither here nor there).
All this said, I don't have a better suggestion. As I mentioned I took the Coursera class and read the Staircase book. The Twitter stuff online was useful but mainly I just read as much as I could online, tracked down conference videos, etc.
