Orange:I've seen the OS X and it's so cool and easy to use. Unfortunately it's quite too expensive...
The price of a Mac hardware does not stray too far from a PC with the same spec. The don't sell low end machines though. The OS itself is cheaply priced. Mac OSX Leopard costs USD200 for a family pack (5 user license) while Vista Ultimate costs ~USD300+ (single license).
Orange:What kind of programming language did you use?
Mac apps are written using objective-c and the Cocoa framework using
Xcode as the IDE. I've also tried ruby on rails and java+eclipse in there.
OSX is just bsd unix with a very pretty wrapper so there are a lot of programming languages available to you.