You won’t notice any difference unless there’s a problem, but I finally broke down and upgraded from WordPress 2.0.4 to 2.0.5 only a month after it came out. I let my mom’s blog be the guinea pig (don’t tell her I said so!) and everything went smoothly, so I decided to take the plunge.
First I backed up the files to my hard drive then backed up the database. It was easy as pie. All told, it took less than three minutes if you don’t count waiting for the FTP client to finish transferring files back and forth.
If you’re still running 2.0.4 (or an even earlier version) you will probably want to think about the upgrade, especially since it includes some security updates according to the official WordPress blog.