Choice of language is pretty much a matter of comfort when you're first learning. The question is, do you want to be using Ruby/Rails or PHP/Wordpress/Codeigniter/etc. If you're just learning, you're going to <i>want</i> to code in whatever language you choose.
Just for reference, you can create backends for websites in Clojure, Java, Python, Haskell, go, JavaScript(node.js), etc as well.<p>I'd say use Ruby/Rails if you want to create webapps and PHP/etc if you want to create Wordpress sites.
Someone more experienced than me in these languages can comment further.<p>Heroku.com supports Ruby and from using it with Clojure and node.js apps, I highly suggest this route even if you enjoy setting up your own servers.
You can also use providers like Amazon EC2/Joyent/Rackspace and set up your own box to be either a LAMP stack or Ruby/Rails.<p>There is a long list of Databases to choose from these days, including: MySQL, PostgreSQL, Riak, CouchDB, MongoDB, Cassandra, etc.<p>Truly the answer you're looking for is "Just start somewhere". The amount of tech you can choose between is dizzying and you'll eventually get to a point where you can make your own decisions if you just keep hacking.