IMO, there are a few reasons to create partitions. Either, to overcome file system limitations (FAT16, FAT32, MBR) or you want to boot several different OS from the same drive (virtual machines make this practically obsolete).
if your still using FAT16 and FAT32, there are a few other innovations you need to be introduced to before partitions.
The specific recommendations are outdated but making 2 paritions is still a good idea imo (whether they are logical partitions or 'hardware ones' - SSD/HDD for enthusiasts - isn't important.)
Parition 1: OS, programs, etc
Partition 2: data, save files, personal files, media, etc
That way if you want to simply reinstall or upgrade the OS (which ought to be done fresh imo) whether because you have to because the OS is hosed or you want to because of an upgrade all your data is intact and you don't have to waste time pre-reinstall moving files about. Whatever way one accomplishes this it's usefulness can't be denied.
Since my hard drives now contain 20 + years of work and data, the first thing I do is build another separate computer, clone the existing drive with Copy Commander, and then insert new drive in new computer and install everything and then use cloned drive to copy over data and such, that way if I pull a brain fade its the clones partition or new drive partition I toast and not my original. System reinstall work the same.... Clone first.. work with the clone. If its a suspected drive problem, clone, and then clone the clone, that way you don't have to touch the original more than you have to, you can just keep copying the 1st clone and trying different "fixes".
Multiple partitions is a guarantee that one day your are going to screw yourself out of some important data. You are either going to install the OS on the data partition, trashing your data, or your false sense of security is going to let you take down a whole drive with your data going with it.
I don't even start to manually partition a drive anymore.... Unless its a situation where I am migrating a system copy from multiple hard drives and absolutely have to.
The option in Copy Commander that says "Automatically copy to empty disk" will not copy empty data over my original, but I have been tired enough to copy the empty disk over the original before.
Managing partitions is an unnecessary complication. How do you size them? Are you talented enough to resize them and move data when one maxes out? Believe me, its going to happen. I consider myself a former partition victim, and if you are going to be one, get the right tools...http://www.partition-recovery.com/
, Copy Commander(or your favorite clone tool), Acronis (whatever the latest is), and a couple versions of Linux and windows and partition you little heart out. Screw some of them up, put data on them, delete them, resize them, and the recover them..... let me know how much fun that is.
Nice new large HDD's are like $100 now, my software maintenance is over $5,000 (maintenance BS, it a yearly fee for updates) per year, and I probably spend $10,000/yr buying new software, buying 10 or twelve new hdd's every year is not that big of a deal, its the time managing them that adds up.