Framework + DB + Server + Hardware?

Framework + DB + Server + Hardware?

I notice that I used the google translator for this question.
I have a project in mind. Perhaps not very large, but in order to learn.
I would like to create a social network, twitter style. People could post
and comment on it, change your profile picture, etc.
For a few weeks, I implemented a part with Symfony2 (PHP) + Bootstrap
(CSS) + MongoDB.
I used several symfony bundles such as FOS, but hey noticed that on many
occasions I had to reinvent the wheel (maybe for my ignorance) ...
I was reading about Ruby on Rails, and I was in love. In view is very
similar to twig, and models is easier than doctrine (which is not
difficult).
Going to the point.
What do you recommend to develop?
Ruby is a good candidate? What database do you recommend? (I think NoSQL)
Speaking in terms of hardware / server:
Debian 7 or CentOS? (Never used CentOS)
Tale with little money, and I'm the only effort in this project.
Eh just purchased the RAM (haha), but the following features are the ones
that I have in mind.
Intel Ivy Bridge Core i3 3220 2GB 1600Mhz Ram (for now) 1TB SATA3
(recommend SSD?) Asus P8B75-V Gen3