First of all, I've decided to try and migrate from PHP to Ruby (on Rails) for future and current development projects. I remember reading the strange and wonderful "Why's poignant guide to Ruby" a few years back but never quite having the time to get into this inventive, new language. Of course, now, Ruby on Rails (RoR) is perhaps the hottest ticket out there, with all the Web 2.0 and Twitter being all the rage and RoR having all the great tools to make programming of 2.0 websites easy and dare I say it - fun. :-)
So, I started reading again. Obviously the Agile Web Development book by mr Hanemeier Hansson, and a great little book called Simply Rails 2 which I thoroughly enjoyed. I also bought Programming Ruby 1.9 , which is very well written. In fact, I really like the books from the Pragmatic Programmers' bookshelf. Great stuff! Ended up buying their Advances Rails Recipies, too, but haven't had a chance to check it out yet.
I kind of stumbled into Ruby again because I was looking for a good XML browser. And what I found, and fell totally in love with, was Nokogiri. This is a fantastically fast XML/HTML browser, which supports CSS3 and Xpath. This Ruby gem has great documentation, and has made my life so much easier. If you need to handle a lot of XML/HTML, go for Nokogiri! Can't recommend it enough.