Former Microsoft-focused dev here. It's funny you mention fads, because I feel like most of the successful development decisions in Microsoft frameworks arose from copying previous 'fads'. Once you deep dive into OSS, you start to see where Redmond got most of its influences.

Here's my current OSS stack.

Framework: Ruby on Rails

Language: Ruby

Web Server: unicorn/nginx

Data Layer: ActiveRecord

Database: Postgres 9.1

OS: Linux (Ubuntu Server)/OSX

Editor: Vim/TextMate/SublimeText

Training: PeepCode, RailsCasts, CodeSchool, Pragmatic Publishing books, local meetups, you name it.

Technical References: Ruby and Rails API docs. GitHub.