Sync program

[briareos_kerensky]

I have a rather large directory (around 300 GB) filled with multiple files that I back up weekly on a NAS. For this purpose I use DirSync Pro, a free Java program that scans source and target directories and synchs them.
However analyzing such a large directory takes hours, and I was looking into a better solution.
I tried with TortoiseSVN, that I already use for other purposes, but I don't really need subversioning those folders and it takes way too much space, even with just the repository and no subversion active.
I quite like the fact that Tortoise tracks any modification of the directories without the need to scan them every time: is there a program to just sync two folders and keep tracks of the changes made between "commits"?

[S3M]

Not sure if it meets all you needs but we use perforce at work, we used to use TortoiseSVN but perforce is better all round.

http://www.perforce.com/

[Brad]

I like http://www.fossil-scm.org/ for it's speed and simplicity

[charlesr]

I use http://sourceforge.net/projects/freefilesync/ (free file sync). Far more amazing than I expected it to be.

[briareos_kerensky]

FreeFileSync does what DirSyncPro does (analyse, then sync), I guess I'll try Fossil, Perforce seems too much for my needs (and the free version has a monthly file limit which I'll surely break).

[charlesr]

I have 400GB of stuff. Ok, so not much of that changes each time, but it doesn't take long to scan.

What about something that uses rsync like: http://www.aboutmyip.com/AboutMyXApp/DeltaCopy.jsp