Hi Bet, you'll get great satisfaction out of using any Apple Mac. The layout is a bit different to Windows, but once you get used to it, you'll never go back, consigning Windows to where it belongs in the late Jurassic age. It is far more user friendly, click and drag for most things.
The 13 inch macbook sounds a tiny bit expensive, though it depends on what's under the hood. I think you might even be able to get a MacBook 15 inch for a hundred or two more. Doesn't sound like much difference, but for graphics, can't beat a bigger screen.
Quick glossary -
Processor - this is the chip that does all the calculations and 'thinking'. The faster, the better: the more 'balls it can juggle in the air at a time without dropping any'. Measured in Hertz. Most MacBooks have processors of about minimum 2GHz, which is fairly fast.
Hard Drive - the memory bank, how much info you can store. Measured in bytes - usually millions of bytes these days (Gigabytes - GB) Typical hard drives range from 40 to 320 GB. Don't forget that the faster the memory disc in the hard drive spins, the faster you can store and retrieve data. If you are getting a new mac, I'd suggest going for the 7,200rpm option instead of the 5,400rpm, if it's available. You'll have less freezes and time for opening files will be shorter.
Processor memory - as well as needing to be fast, the more temporary memory a processor has, the more info it can handle at a time without having to save to the Hard Drive. Most Macs come with about 2GB of this kind of memory, i'd recommend upping it to 4GB if you can. The extra 2GB will prove their worth when you want to keep several programs open at the same time, or use graphics- heavy programs or want to edit your home movies.
These are the most important technical aspects of buying any computer and it's worth getting the best specs you can afford, as it saves getting frustrated later on, and it's always more expensive and hassle to try and upgrade them within the same computer later on. If you plan never to use the computer for anything more than writing letters and checking mails though, it might not be worth adding the higher-end customizations.
OS X - The Mac uses an operating system called OS X (the X stands for '10') which is totally different to PC Windows. This means that programs for PC won't run on Mac, so when you are in the store and you see a new game or whatever, you need to check it says "Mac' or "PC / Mac" before you buy it. Unfortunately there are fewer programs for, and they more expensive than PC, but the gap is rapidly closing and most of the important programs like Microsoft Office have been available for Mac for some time as well. Any Powerpoint stuff or Word stuff you do on Mac will be compatible with similar PC programs, so you can use them on both computers. Mac even has a thing called 'Virtual PC' - basically it's a program that sets up a compartment within the Mac's memory and installs a Windows-like program so that you can run Windows programs on the Mac. I never bother with it - the Mac versions are better anyway.
Macs are also the industry standard for graphics programs, they are streets ahead of PC in this regard, plus they are generally more reliable, the 'BMW' of computers.
iWorks - The iLife'08 programs aren't great, sadly, the new version of the movie editing software (iLife Movie '08) is a dreadful regression form the previous version, but happily it's not too hard to find the older version iMovieHD which will run fine on your MacBook and does a great job of movie editing with minimum fuss. iWork is part of the same platform - generally it's crap in my opinion. You'd be better off spending about 50 dollars to get the Microsoft Office for Macintosh.
One thing to note - while PCs import movie and camera files through a USB port, the Mac uses a thing called Firewire or Firewire800. It's still basically a cable to connect the camera to the computer, but just has slightly different connectors. You might also find yourself having to buy a few additional cables and adaptors in order to connect your Mac to the average projector. Also when buying hardware (external hard drives, printers and scanners) check that they are compatible with Mac OS X. Most are, nowadays, but sometimes companies forget to include this info in their 'minimum specifications required' panel on the box, so you can ask them directly.
But once you get a Mac, you'll find the experience so pleasant compared to PC you'll never look back. You've had some experience with Macs already, the latest generation are a joy to use.
There are loads of websites reviewing Mac products as well, have a glance over some of the customer reviews. Feel free as well to PM me or ask anything more about Macs if you feel something isn't covered above.