good move for you Rich! yes, a mac or macbook has a lot of advantages though there are downsides as well. i used to have a macbook (white) and used it for 2 years then i upgraded to macbook pro and i just love it.

aside from its ease of use, its very popular for its multimedia capabilities. most artists i know use garageband (though i dont use is at all) in composing music. Such ease of use is a characteristic cited by owners as one of Mac's chief benefits. Everything about a Mac is coordinated to produce a computer that fulfils a wide-ranging set of tasks in as simple a manner as possible, without compromising creativity and fun. From the clarity of the display and ergonomic features of the keyboard, to the most sophisticated graphics software, Apple has made each Mac's hardware and software simple and accessible. This is why Macs prove so popular in schools and colleges.

The upside of the White MacBook is firewire, a real important feature for amateur and prosumer musicians and videographers.

yes, you can use windows files and even use windows there (there are several software that can do this, i use Parallels).
it is a good step for you to switch to mac..
The process of moving your files from a PC to a Mac is straightforward. Just download the files to a USB or FireWire hard drive and then plug this into your Mac. Alternatively, use a network, or ask your Apple shop to do the job for you.

well there are a lot more to talk about, maybe you can drop by http://qmug.webs.com, there are some mac user folks who meet regularly in doha, they can assist you in so many ways.
hope this helps!