Swap space is used as a backup memory location for stale files or when you exceed your RAM capacity, just as the paging file is used in windows. If the memory is completely filled then the system will crash, even though you have a high amount of RAM a memory handling error in an application may fill your RAM and cause a crash if swap is not enabled. If you have swap you will notice the system slowing prior to crash and give you warning to find and stop the problem app, this issue is very rare, but it is a good precaution.

Some distros will work without allocating swap space, but with your large amount of available space it would not hurt to allocate a small 1G swap partition.

To add to what mfillpot has stated, you can't install linux without a swap partition.