Advantages/Disadvantages of Partitioning a Drive

"I strongly recommend you to do the partitioning. It makes sense.

Advantages

Formatting Convenience - If you ever need to format, you do not have to copy your data out first since it resides on another partition. You can just format the OS partition.
Increased Security - There is increased data security, since your data is now on another partition. Malware that affects or scan files on only one single drive will not scan your data partition.
Improved Performance - you can defragment your OS drive for max performance, and not worry about it being fragmented so fast, since data (where it changes the most), resides on another partition.

Disadvantages

Slower Data Moves - Moving data from one partition to another takes awhile, unlike moves in the same partition.
Set-up Inconvenience - There are advisable steps to do in order to let your OS use the other partition as data effectively without impacting your workflow. e.g Moving your My Documents folder to the other partition.
Reduced Space - When you have 2 partitions, some space is lost.

That said, you definitely should partition. In fact, I recommend THREE partitions. OS, DATA, CACHE. Been following this style for years, and never regretted."

"I realize that this is a Windows question and that there are advantages and disadvantages in partitioning but it is worth looking at how Linux distributions evolved.

A few years back almost all of them partitioned heavily between various components (temporary area, a few system ones, user data). I see that this is getting rare now, the main ones just have one large root partition with everything in."