I have a new laptop with ATI Radeon Mobility HD 3670 and I have been reading about drivers and stuff, which brings up some confusions I have had for a while now. So I'd like to ask some questions. I only hope to get some short answers, nothing fancy. Here it goes:

1 - What is the difference (if any) between fglrx and catalyst 9.1?
1.1 - If any, what are the pros and cons of each one?

2 - I have read in many places things about direct rendering, aiglx, xgl, desktop effects, and games.
2.1 - Are they AIGLX and XGL bound to nvidea or ati? (I have seen tutorials that go for aiglx if nvidea and xgl otherwise)
2.2 - What is the relationship between aiglx/xgl and desktop effects in ubuntu?
2.3 - I think I have an idea of what direct rendering is but I want to make sure. Is something being directly rendered when the graphics board is doing the calculations involved and indirectly rendered if those calculations have to fall back to the cpu for some reason?
2.4 - Can you currently have an ati card with direct rendering and desktop effects in linux? If not, why?

3 - Is video playback dependent of the graphics board?
3.1 - When I play a dvd, is the graphics board doing something to "render" it?
3.2 - Or it only has processing to do when uncompressing certain video formats on the fly? Some codecs that store more abstract information that can be translated by the graphics board?
3.3 - Are there any special relations between gstreamer/totem/mplayer/flashPluginForFirefox/whatever and specific drivers for the graphics cards?

I would like to have some minor desktop effects, like window thumbnails in alt+tab, wobbling and the cube thing, efficient video playback and, occasionally, play some neverball or 3D chess. I hope your replies can help me enhance my understanding and make the best choice towards what driver should I install.

Sorry for the long post, but these are doubts I have had for years and I would like to sort them out sometime

Thanks a lot in advance