I have a tip for Linux users, and people planning to install Linux sometime: get used to keeping the OS and user data separate. These can even be on separate disks (ideally) or partitions.
A bit of history: this notion of keeping user data separate from the OS files is good advice on any operating system, but it's an idea that Windows users have some trouble getting used to, despite Microsoft's recent attempts to enforce it. Windows switched from a single-user OS to a multi-user OS when they brought out NT, so there's been plenty of time for people to get used to this, yet I still see people fighting this idea. (How many of you share one account across a whole family?)
Under Windows you have a folder called "Documents and Settings" (NT, 2000, XP) or "Users" (Vista, 7). Under there, each user has a folder, and all that user's data should go under there. That way, it is hidden from other users. and it's easier to back up.You might say that Windows is becoming more UNIX-like, though NT was heavily influenced by VMS, the OS that ran on DEC VAX systems. (Several VMS designers joined Microsoft to work on NT.)
Under Linux, you have the same concept, but it's called the /home directory. When you install Linux, you might be presented with an option to put /home on a different partition or disk. There is a good reason to do this: if you have to reinstall the OS later, you can wipe the OS partition without wiping the data partition, so data is not lost. During the new installation, you tell Linux to mount that partition as /home without formatting it, and all data and settings are back.
It was funny to see complaints about the security features introduced by Microsoft in Vista, when all they were doing was enforcing the kind of security that UNIX systems have had all along. I think the reason why it became a problem has to do with many applications, especially old ones, being written in with a "single user" mentality, not understanding the need to clearly separate system and user data. It makes sense that Administrator (or root) rights are required when you install an application, but after that it should run without needing Administrator rights.
Anyway, if there's one point to remember, it's this: under multi-user Linux, you will only need root rights for specific tasks, such as installing an application or fixing something. At all other times you will work as a normal user, with your own data and settings distinct from other users and the system. On my Ubuntiu Netbook system I don't even have the root account enabled: I use the "temporary elevation" system (sudo) when I need to do any system maintenance tasks.