LVM Physical Extent

I have done a number of searches with Google but all the explinations are either very vague or to complex for my level of knowledge.

When setting up my partitions in CentOS I am asked what I would like my LVM's "physical extent" to be. It defaults to 4MB but it also gives me the options for 1MB, 2MB, 8MB, 16MB, 32MB and 64MB. This partition is created accross two Ultra320 SCSI drives, will be around 150GB and will be for the /home content.

Just curious what the best selection would be for my needs? ...and maybe a breif explination if possible...


Thank you for any info