Intel Mac :: What Tool / App / Mac Feature Can Use To Copy Docs Between Computers

I have an iMac and MacBook Pro, both have Snow Leopard. I use Carbon Copy Cloner but only to back up the iMac to an external drive. I do not want to create a bootbale drive of the laptop (not enough space in the external hard drive).What I want to do is ocassionally copy files from the laptop to the iMac. I know how to do this via sharing but sharing does not really let me back up only new files. In other words, upon my periodic file copying backup from laptop to iMac, I would like whatever tool or app or program or Mac feature you may suggest to detecte which files already exist in the iMac. So, pretty much the same thing CCC does but not a bootable drive, just copy files. I also want to create a file copy back up of some of the applications in the latop. I dont think drag and drop or sharing would work for this. Really, I would be satisfied with some kind of snapshot if you will of the applications and versions in the laptop.