First, FAT32 pretty much guarantees that your drive will work with any computer you plug it into. To my knowledge, every computer and operating system released since the invention of the USB drive supports FAT32. I would be inclined to go with FAT32 for a flash drive, but NTFS for an external hard drive. Here’s why:
Virtually every operating systgem modern enough to supporft USB ports can read and write FAT32. That’s not the case with NTFS. For instance, you need a third-party utility to write to an NTFS drive on the Mac. Believe me, you don’t want to install software on your friend’s Mac (or the library’s).
Another issue: Flash storage wears out when you write to it, but not when you read from it. NTFS’ journaling feature, which keeps a record of changes to your files, writes to the drive a lot, and will thus shorten its life.
Speed really isn’t an issue. I casually benchmarked reading and writing to the same flash drive formatted both ways. FAT32 proved faster, but not fast enough to worry about. The speed difference was less than 2.5 percent.
So why do I recommend NTFS for an external hard drive? FAT32 can’t handle partitions larger than 32GB. If you buy a 500GB hard drive, you’ll have to divide it into something like 15 separate partitions. That won’t make life pleasant.
And journaling works just fine with hard drives.
How do you format an external drive (hard or flash)?
Plug the drive in and open it in Windows Explorer (File Explorer in Windows 8).
Make sure there’s nothing on the drive you want to keep.
In the left pane, right-click the drive and select Format.
Select the appropriate File system and click Start.