I use my OSX laptop as my primary desktop, but I work on more then 20 linux servers. For me it's important to have a good vim and screen configuration. For syncing my conf files I use "roaming homedir" (http://roaming.skumleren.net/) together with git and a personal setup script. I takes me 10 seconds (one command and few yes/no answers) to setup of update a virgin home dir.

For that reason that it doesn't exist on Linux, I'm buying an expensive vmware app. I'm realy addicted to illustrator.