You should start with Ruby, Rails, SASS for css, HAML for html, you should write your code in Aptana Studio, and deploy with Engine Yard or Heroku, Aptana has deployment wizards for both. Oh, and GIT for version control.
My personal suggestion is to go with Python on google app engine. Use a simple text editor. The implementation is simple and has slightly less "magic" going on than Ruby on Rails. Once you've got it running in GAE, you'll have a better understanding of the request/response cycle and an appreciation of getting variables from forms manually. Then do the same project in Rails (or Django if you prefer Python). Once you understand the manual approach of dealing with forms, you will have an appreciation of what's going on behind the scenes when Rails magically does some processing for you.
After that you can iterate again and add to your skills learning about SASS, HAML, finding the "perfect" IDE etc.
Start as simply as possible, learn a little about what is going on behind the scenes, then grab tools that help you automate the boring bits.
In fact, if you didn't already know some Python and Ruby on Rails, I would suggest just hacking out some nasty PHP to get up and running (simply because it is so widely supported and saves a lot of deployment hassle when you just want to get the thing working)
google app engine
Python and barebones html form processing would be the place to start.