I was a long time DOS/Win user and made the switch to Mac OSX 4 yrs ago. I find this software very intuitive and the learning curve is pretty short. It just works, and adapting to OSX is much easier than you think it will be. I originally signed up for the $99 training classes but the ones I was interested in were very impacted so I never actually went. I would benefit from a little training in iPhoto and iMovie but everything else is pretty straightforward and intuitive.
Instead of buying an expensive version of Microsoft Office for Mac, I chose to use Open Office software which is very flexible and compatible with nearly every other file format... and it's free online.
Apache OpenOffice for MacOS X
Enjoy your new adventure!