Mi amas Esperanta! I'm learning quite a bit (Mi lernas multe?), definitely the fastest I've ever picked up a language.
The beta course seems very stable and I'm quite impressed. Can't wait for the mobile apps to roll out. Has anyone gone on the the next stage after finishes Duolingo (which rocks)?
I bought some beginner books from Lernu and off Amazon but there's not many resources that I could find. Also, unfortunately there's no meet up in my area for Esperanto enthusiasts. If anyone else is in San Antonio TX and would like a meet up let me know!
I recommend Memrise for vocabulary training. The course I'm currently using is this one, which seems very good. There are some minor errors still and it seems like the creator is no longer around (though I plan to try and track them down when I'm done with it entirely to point out all the feedback I posted on the forum), but it's already high enough quality, I think, to be well worth your time. Also, if you ever get through that monster, you'll have a very good basis for pretty much whatever you want to do with Esperanto, I imagine. Well, almost :)
Oh, be aware that the lesson order for that one is a bit strange; you should start with lesson 87 and move onward from there to the end, then continue from the start. The numbers in the titles of the lessons should make it clear.
If you want to start with a slightly smaller one, consider this one here. I did that one beforehand, but if you're gonna do both, there's a bit of overlap.
This sites has lots of books http://esperanto-usa.org/retbutiko/index.php?main_page=index&cPath=20
I'm honestly not sure either, what I do know is learning it is fun and easy(ish) and so it gives me more confidence to learn. I've spent years trying to learn French but I haven't reached Fluency with Esperanto I can see that happening in less than a year. This may sound silly, but I think that once I learn one foreign language I'll be much more able to learn another.