Backups on a separate drive my friend, backups! For whatever reason, some people dislike multiple partitions on the computer. My spouse wants a C: drive and that's it!

I don't like having multiple partitions on a drive either. I always burn the backup partitions for my netbooks to a DVD and then reformat the entire drive giving me an extra GB or two. This may not sound like a lot but it really comes in handy for netbooks with 16GB or 32GB SSDs where every GB counts (a 16GB SSD will often give people 11-12GB of storage by the time the partition is added, that isn't a whole lot). Asus also likes to split their 160GB hard drives into two ~75GB partitions, it annoys the hell out of me.

I don't mind having multiple hard drives though. One drive used for primary operation and then another one used to store all of my media and as a backup for my primary drive.

I have found Windows' ability to map partitions to an empty folder to be very handy for this. One C drive for the user, multiple drives in reality.

I personally partition the first (physical) drive into 2 partitions: 25 GiB for the system, rest for non-program non-system

The next (physical) drives are all formatted into a single partition.

If you can add different hard disks (instead of partitioning) it will be great, however it is not always possible (it's expensive and some laptops can only handle 1 hard disk).
Since I'm a linux user, I need at least 2 partitions / and swap. I also have a /home partition, so If i run out of space on my home it won't affect my system stability.
Here you can check the Debian recommended partiotioning scheme http://www.debian.org/releases/stable/i386/apcs03.html.en . Note that in multiuser systems the recommendation is create up to 6 different partiotions: /, swap, /home, /usr, /var, /tmp.
So, I neither hate 'em or like 'em. In some cases partitioning is recommended and also a good practice, but other times it could be a little bit annoying.

If the computer that I am using only has one hard disk, I create a partition just for the OS and programs, and another one to save any media or documents. The upside to this is that you don't need to worry about losing those files if you need to reinstall the OS later. This method fails if the hard disc crashes though- you lose both partitions. Another con is that you kind of need to guess at about how much space you will need on C: for the OS and programs as this can be hard for a novice user and depends on your personal situation. Multiple hard disks (one physical hard drive for the OS, and one or more physical hard disks for media and saved documents) are a step up although if something happens to the whole computer (theft, fire, flood, ect.) then you are still screwed, or the document and media hard disk can still fail, losing all your work. Obviously the best tried-and-true fail-safe is to create a back-up of the media and documents outside of the computer (flash drive, dvds, ect.) every so often.