I hate thieves. I really really hate thieves. Two years ago my Canon 40d was stolen from me on my birthday. I remember it vividly because nothing is so instantly sobering as having a part of your right hand taken from you.
Flash forward to two years later and it happened again. This time it wasn't my camera so much as it was camera bag with lenses, flash, and all sorts of other knick knacks inside... Not to mention that they tried (and failed) to steal my car. Don't worry though, they were kind enough to cut the cables to the battery to make sure I wouldn't drive around all angry.
Fortunately this theft has allowed me to re purpose my gear (yay insurance!) to the point where I can focus (no pun) more on the kind photos I have to do in order to have money to do the photos I want to do. Turns out stuff is replaceable. It also makes for a great conversation starter at any and all camera stores I visit over the next week in order to re-organize and re-energize my "Aresenal." I've already replaced my flash. I forgot what it was like to handle one that is all shiny and new...and hasn't been dropped.
All in all the experience has taught me that no matter how tired I am, I should always carry my bag upstairs. Always always always.