I usually used windows for developing desktop applications, but recently I've almost abandoned desktop apps and have been doing web development so much. I'm using many web technologies and languages, especially Ruby on Rails, and I'm facing too many problems using windows. Besides, I personally want to move to Linux.

So, what's the most helpful and comfortable Linux distribution for web development?

I have a short but handy experience using Ubuntu desktop, so I'm familiar with the generics of Linux (like -as a simple example- using the command line), and I don't have any problem in getting used to any distribution (I know I may face some difficulties, but again I have no problem), I only want the best one for web development (especially rails!!).

If the question doesn't belong to this site, I'll be glad to migrate it to the appropriate one.