[wplug] Compare and Combine two user accounts?

[Douglas Green]

The problem: I had a laptop and a desktop, sold the laptop, and transferred the entire user account onto my desktop (as a new user). I now find myself searching for documents that are fragmented across two accounts- the original desktop account and the old laptop account.  Complicating the issue, I bought a replacement laptop which adds yet another account to the mix. 

Is there a way to utilize diff or rsync on my user accounts and combine all the data, setting, and applications into just one user file? I'm sure I'm not the first person to have this issue, so if there's another strategy please let me know! I'm definitely going to be more careful in the future about data fragmentation across devices- this is becoming a real problem. 

Thanks! 
-D