Well, most of you have the same views as I do when it comes to customer service. A quick Hello and then leave me to do my shopping. That's how the store I work at runs. Sometimes people get very "I'M JUST LOOKING!" with us and we simply say, "great, let me know if you have questions that come up." They then look at us with disbelief in their eyes, like we aren't going to really truly leave them alone.
Kev just started a new job. He noticed on the first day he was there that the folks that work there didn't even acknowledge people as they came into the store. He is managing a record store. This store has much theft. My thoughts (and his as well) were if you greet people, and look them in the eye, they might just be less likely to take things...at least that's my theory. Oh and making people check their bags in at the front desk would be the best idea too.