Python and Ruby are pretty equivalent in terms of what you can do with them. Given a choice between the two, I'd probably choose Ruby, as I personally find it to be less cognitively dissonant than Python.

I'm really not fond of having to haul the self parameter around all over the place in Python, and there seems to be some confusion between what's a function and what's a method. (Some of this is being addressed in Python 3 I think.)

The whitespace thing, I can just about cope with, but I always miss the colons off the end of lines. Oh, and at least on Windows, the supplied documentation is organized in a seemingly arbitrary manner (but at least it has an index if you know what you're looking for).

Having said that, Python probably has a better standard library than Ruby, so, meh, learn both and see which you prefer.

"..but I always miss the colons off the end of lines"

Well, if you miss them so much, just put them in.

Yeah, that's what the interpreter says... :(

Chicks love rubies, but don't like snakes that much. :D

Seriously, you should probably learn both.

well if you already know one, you might as well spend the time to learn something else that would give your brain a level up.

yeah, a good tip, but still if you know one, you should at least go through the other ones tutorial just to know what you're missing :D