For Linux desktops, when Windows compatibility is not an issue, which file system is preferred for USB sticks? For example ext2, ext3, ext4, btrfs, nilfs, or even NTFS? Would journaling wear them out prematurely? I heard it's better to mount with noatime option, but how to set it if it's used across many computers?
All decent flash devices perform internal wear leveling so the journal won't wear them out ( too ) prematurely, so ext4 is fine from that perspective. The problem with using most unix filesystems across multiple computers is permissions. If the different computers do not have the same set of users with the same UIDs, the ownership will be wrong. For this reason, it is generally better to stick with fat32, which also allows you to share with Windows. As an alternative, you can use UDF, which can pretend the files are always owned by the interactively logged in user that (auto) mounted the drive.