I went from using XP for most of my life to using Macs much like you're thinking of doing and haven't looked back since. I was a little nervous at first due to some stories and rumors I've heard about how Macs just won't work with PCs and you can't share files, etc. I found all this to be untrue. I picked up a copy of Microsoft Office For Mac (Student/Teacher Edition) and haven't had one problem synching, emailing, sharing files, etc. with XP machines. You can look at Apples website for more info, but here's a few of my favorite features on Mac OSX and my new MacBook.
1) Built in spellchecker in Safari.
2) iLife. I think you mentioned that you like to work with music/photos/videos. Well, iLife has you covered. iPhoto, iMovie, iDVD, and Garageband are all great programs that I use a lot. I use Adobe Photoshop for serious editing, but you'll be doing that on a PC too. No PC comes with this great (or any really) bundled software.
3) Built in iSight in my MacBook along with PhotoBooth. Great for quick video chats on the go or in coffee shops and PhotoBooth is a great app for taking pictures of things around you and sending them to people without having to use your digital camera.
4) Spotlight. Amazing search technology that searches not only all your text/video/photo/music files but also emails, etc. and does it all incredibly fast. I abandoned organizing or even thinking about making folders long ago thanks to Spotlight.
5) No Viruses. Okay, so THERE ARE virus for Max OSX, but most are simply proof of concept, none have ever been released wide spread. Plus, compared to Windows XP (or any copy of Windows) OSX is far superior. Grab a virus protection program to be safe when you buy a Mac, although you'll probably never have to use it . . . ever.
6) No crashes. I've had my Mac for over a year (my MacBook for only a month or two) and haven't had any crashes on either system. My old Dell made is about 2 months before it started crashing regularly.
Okay, there you are. Visit the Apple site for more or, better yet, go to an Apple store and try one out. Sorry for any spelling errors, I'm too lazy to edit this . . . oh wait, I don't need to, Safari has a built in spellchecker. Peace Out.