This is not a generic spaces vs. tabs thread, we already have one of those.
And Python itself has a PEP 8, stating among other things:
Never mix tabs and spaces. The most popular way of indenting Python is with spaces only. The second-most popular way is with tabs only. [...] For new projects, spaces-only are strongly recommended over tabs.
I'd just like to know.. what do you people usually use IRL? Including what you're subjected to in projects where you don't make the decision.