Should I use 32 or 64bit Mac OS X apps? I have a 64bit Intel Core 2 Duo MacBook Pro. A lot of times, software that I want to use is offered in both 32 and 64 bit.

What version should I prefer?

I know that even some Apple's apps are not yet 64bit - I guess this means something. I also have read that there is no big difference except for maybe driver software. What do you think?
You should go for the 64bit version. Apple is more and more leaning towards 64 bit adoption.  

In the end, unless it's some heavy processing application, you won't even feel the difference with the 32bit version. But at least you'll be ready for the future :)