Sync programs?

Are there any programs that allow you to sync your flash memory drive with a specific folder on your mac so everytime you plug it in it automatically updates that folder?

I'm asking this because I use my flash drive a lot and sometimes I loose track of where I put the information. I would like to save the information on my computer every time and simply plug that flash drive in and have the computer execute an order to replace that folder on the flash drive with the one on the computer.

Thanks

I use Chronosync and find it to be perfect for everything to do with synchronization .

It will sync folders, files, over networks, it really does everything.

Yeah Chronosync is very nice.. I also use TRI-Backup once in awhile also.