Protect against SSH hits - http://www.fail2ban.org/
Use this to protect against your ssh attack. A good implementation discussions is written in this webpage. go through it.
Encrypt your USB drive - http://www.truecrypt.org
More than just a Thought! If you are holding some important information in your thumb drive, make it a point to encrypt it. As these flash drives get larger(4-8GB is common now), its only natural we tend to back up a part or most of our hard drive files to it.
There was a recent report that 1 in 7 usb drives are lost in 6 months. Encryption is easy to do and will save you a LOT of headache.
This is one of the best http://www.truecrypt.org/ and its free. Play with it. It takes about 15 minutes to set it up on multiple devices. Once its done, it is on the fly encryption, so you dont have to worry about leaving traces on your harddrive.