I think str8liner summed up a lot of things best. That being said, I do like Sean's idea about pulling them aside and giving a gift card or something of the like. Taking company truck home is also a liability. What if there is an accident, even if your vehicle is parked (hit and run, shopping center, etc) you are out the money and you get aggravated with the employee. There is also a difference for the long-term employee who had been around 5+ years. They hopefully have more respect for thei job/career and your equipment, company, and image. That should be rewarded occasionally if a pay raise is not afforded.
If you fail to plan ..... you plan to fail.