I tend to agree with the Grassman that money really is the bottom line with employees. I also think that if you do some of these little things and don't pay your employees well it tends to come off insulting and doesn't work.
Having said that, if you do pay your employees well(I'm told by other I overpay my guys but I believe they are well worth it), then it is good to do other things to remind them that you consider them a very important part of your operation. I like to pull the guys aside individually and just tell them they're doing a good job and ask them how they are doing. On cold days I might surprise them with new gloves or something like that. These things do go a long way, but Grassman is right that they only go along way if you are paying your guys well.