I'm not trying to hijack this thread but thought this is an interesting subject, at least to me.
Like the OP, my bitcoin client is on my laptop that's not mining. I turned on my client to get the latest block (and my earnings) 2-3 times / week. Then I turn off the client, back up my wallet.dat file to a couple of USB drive.
Unlike the OP, I don't have the $$ to have a dedicated pc / laptop just to run the client. So I do use the laptop on a daily basis.
I have read one of the comments and the term "mobile wallet". How does that work? Is that where one installs the client in that USB? Was that the idea and is that possible?
The mobile wallet is basically a bundle of the application (bitcoin.exe) and the application directory (c:/users/currentuser/appdata/roaming/bitcoin) in one place, typically a USB stick or separate partition. You can than run the application with the appdir= flag to point to the mobile directory.
I personal do this on an encrypted USB stick. I have the app and app directory in a bitcoin folder and run the exe from a bat file with the arg.
Run bitcoin.exe datadir="%cd%\bitcoin
Which has the bitcoin.conf file in it as well as the other goodness.
There's a good post on this in the forums. My syntax maybe wrong. I'm on my phone away from PC =\