Indentation with spaces and the tab key in Eclipse. I've pulled quite some hair on this one and now that I found the solution, I decided to write it down, so I don't have to loose my precious hair anymore.
Everybody has its own preferences, but I like 2 space indentation for PHP (code style of Drupal) and 4 space indentation in Python. And when I press the tab key, I want to increase the indentation level, not insert a tab character. Doesn't seem like much to ask, but it took a long and frustrating process to get this working in Eclipse (3.5 aka Galileo at the time of this writing), Aptana Studio actually, with PDT for PHP development and the excellent Pydev for Python development.