Welcome to Apple Support Communities.
Apple has made it easy to migrate. Check out Windows Migration Assistant: http://support.apple.com/kb/ht4796 . It does most of the migration job for you. Migration Assistant automatically transfers your contacts, calendars, and email accounts, user accounts and files.
Most of the often-used applications have Mac equivalents, such as MS Office, PhotoShop, AutoCAD... For media files (pictures, music, and movies) the applications may differ but they should read most (if not all) of the MS file formats. There are usually inexpensive conversion utilities for any media files that are not natively compatible. Apple Mail is the preferred mail program on the Mac and it will talk to Microsoft Exchange servers if you need that.
You may want to purchase Mac versions of third-party software applications such as PhotoShop and AutoCAD but that is not absolutely necessary. For applications available on Windows that are not available on Mac OS X or expensive applications you do not wish to repurchase, you can configure your Mac to run Windows and OS X simultaneously (or boot them one at a time).
Service is a huge difference. If you purchase AppleCare it will extend your hardware warranty and free consulting to three years. Apple answers their phones promptly and usually can solve problems over the phone. If you prefer in-person help you just go to an Apple store to have a chat at the Genius bar even if you are not covered by AppleCare or the free first 90 days of consulting.
Hope this helps.
You might consider reading a book such as:
(I have no financial interest in this book, its vendor, or its author.)
I read such a book before I started with the Mac, and it helped me a lot.
Macs are cheaper to own that PCs: http://techpatio.com/2010/apple/mac/it-admins-total-cost-ownership-mac-less-pc
Why will you love Mac? http://www.apple.com/why-mac/
- Better Hardware http://www.apple.com/why-mac/better-hardware/
- Better software http://www.apple.com/why-mac/better-software/
- Better OS http://www.apple.com/why-mac/better-os/
- Better Support http://www.apple.com/why-mac/better-support/
- It's Compatible http://www.apple.com/why-mac/its-compatible/
Switching from Windows to Mac: