One of the best things about having a laptop as my primary machine is that I generally don't have to worry about synchronising issues any longer. For instance, I used to have a USB Drive that was my "transfer device", and I was endlessly copying data to and from it. This meant I had three or more copies of my data, but I sometimes wasn't sure which was the most recent.
I bought Changes.app to use with my Source Control system(s), as it is nicer than FileMerge.app. And it meant I could support an independent MacOS X Developer. And I've been using it, sometimes "in anger" where some data has been corrupted.
Today, I wasn't able to get onto the Wireless network properly, and had my data on my Laptop, but needed to run some SQL queries on a database on a Uni machine. I copied the files across (in a location where the WiFi worked), and then ran the queries on the Uni Machine, but made some changes to both sets of files at the same time.
When I sat down to merge them all, I happened to think to use Changes. I dragged both folders onto Changes, and it gave me a list of files that differed.
I was able to choose which parts of each I wanted to keep, and save them, and it made both files the same as the merged version.
I wasn't really expecting this - I naïvely thought that it was a read-only process, but Changes made it pleasant.