To add to the list of filesystems:
ext2 - OLD and very curruptable, use only for read-only purposes
ext3 - like ext2 but this is a journaling filesystem. If you power off your system mid-copy you should be able o retreave all your files after a rebuilding scan
reiserfs - this is the reiser filesystem version 3. amazing journaling (see above) filesystem with crazy speed. Also allows you to get rid os slack-space*
reiser4 - same as above with alot of speed improvements _AND_ the ability to make any file/folder in your computer into an OOP-like object!
xfs - haven't really used it personally. I hear its very fast, has meta-data journaling...
jfs - IBM's journaling filesystem. It's kinda new and I haven't touched it.
swap - With this you can make your kernel think you have more ram
Lastly about fragmentation - all UNIX based filesystems have a check inplace to fix this crap. Microsoft, amazingly enough, can't make a good filesystem. Good filesystems correct fragmentation on their own. Try to search for a UNIX based defrag utility, you won't find one - well maybe you'll find one for FAT/FAT32 partitions
