1 - Finder. The finder is way faster! I think Leopard is worth the upgrade, just for this feature alone. It's designed much like iTunes so it's very familiar to most people who've used a computer. It even has coverflow like iTunes, so it's easy to find the files you want.

2 - Time Machine. This allows automatic backup of your computer onto a separate hard drive. You don't have to even think about it - just set it and forget it.

3 - Spaces. This allows you to organize your computer with the applications that you use together - and you can keep things separate. With as many applications as I have open at once, I think this will be a very nice thing to have to keep things straight.

4 - Quick Look. If you're looking through files, and want to know what you're looking at, then this is for you. Quick Look allows you to see the actual document without opening the application. This should save a lot of time trying to find that particular file.

5 - Parental Controls. This has been expanded more than ever. You can control how much time your kids spend on the computer by the day, weekday, or weekend. It's really slick.

6 - Boot Camp is now standard. This allows you to boot into Windows. If you have a Windows program that you just have to use, then this is for you. You still have to buy a copy of Windows, but this makes it really fast and easy.