So each time I setup a new Mac with TextMate this always bites me:

Inconsistent indentation: 1 tab was used for indentation, but the rest of the document was indented using 2 spaces.

Then I go digging into ⌘, (TextMate's preferences) trying to figure out where the hell the "use spaces instead of tabs" is buried and scratch my head.

If you look at the bottom of an editor window in TextMate you will see

Tab Size: 2

If you click on that you can check the option Soft Tabs (Spaces) and we are again at peace with the TextMate.