I am going to be setting up my hard drive soon, and one of the things I read is that many linux partitioners will give you the option to leave unallocated space between partitions. Is there any sort of advantage to doing this? If so, how large of a space should be left between partitions?
As far as I can see, there is little benefit from unallocated space. Partitions should be properly aligned on the disk (and that may cause some space to remain unallocated), but most GNU/Linux utilities will automatically do that.
If you're using a SSD made by Intel, you can decrease performance degradation by leaving some space unallocated at the end of the drive. It will be used for temporary storage when blocks need to be erased.