I switched to OSX recently after almost 10 years each on Windows and Linux, and I got used to it in about a week.
The thing that I still haven't get used to is home/end. On OSX you have to do Ctrl-A and Ctrl-E. Home/End moves to beginning and end of the document instead.
That's the only really annoying thing.
Otherwise everything is nice and logical and you'll pick it up in no time.
99% of the time when installing applications, it's just dragging an icon into Applications, instead of clicking through a million steps. Then drag it on to the dock if you want it on the dock.
There's really not much more to it... oh and Time Machine is awesome. It's basically System Restore done right.
Most things just work, and work the way you would naturally expect it to.