Same goes for iTunes - when you import songs into iTunes, it makes a copy into user/Music/iTunes, so you can delete the source file, if it's already somewhere else on your Hard Drive...
Apple's website also has a good list of available software, both their own and 3rd party.
Sadly even Myers, despite often now having a good range of Mac hardware, fails to get in much Mac software...
Thing is - what do you really need? Most business needs have similar if not the same products on both platforms... Yes, there certainly aren't as many games available on Mac as there is for PC, but there's a good shareware community for that. Some of my favourite games are/were share/freeware...