So it looks like the Germans and the Americans do the "20, 30" etc, and the Brits do the "oh X oh".
Silly british. 
It depends on the context.
During a conversation about amiga accelerators I would use oh twenty, oh thirty, oh forty, oh sixty etc.
If that would lead to ambiguity then I would say sixty eight thousand and thirty etc.
For the 68000 I would always say sixty eight thousand. The 68010 would probably always be sixty eight thousand and ten, but it's largely irrelevant.
I used to pronounce linux the way americans would (line-uks), however linus pronounces it differently.
http://www.kernel.org/pub/linux/kernel/SillySounds/ ubuntu is supposed to be oo-boon-too, but it seems to be pronounced oo-bun-too around here. I can't remember using it in conversation, but I'd probably use the latter.
btw I'm british.
