Recommend web-enabled visitor counters?

I am looking for a reliable, affordable visitor counter with a web interface that will give me stats such as busiest hours, days of week, etc. I don't need/want "greeter" abilities; I just want a way to monitor traffic.

There are several subscription services available (on SLX, for example), and I don't know which to choose. I'd like real recommendations from people who've used them. Thanks!

EDIT: I don't know how the different services vary, but I would like one that would let me drop multiple sensors around an island so I could track which areas were busier than others.