I'm always aware of the security of my X50v at work and out in public. One staff member at work had a PDA stolen, so I'm very paranoid there, and never leave it lying on my desk when I have to move around.
Because I use it for work (and store a lot of sensitive information on it as a sys admin) I also encrypt _all_ the data with Codewallet Pro, just in case the worst happens.
Even my contacts list in encrypted