Although Google Analytics is a strong and usually the first choice of most bloggers and webmasters - I have recently been using GetClicky.com
These guys have been around for awhile a offer a really professional and very slick analytics package. I won't do a review here (link below for the full story) but what I will say is - GetClicky is realtime! Unlike Google Analytics, GetClicky updates in realtime so you can literraly see visits as they happen.
Check out the full review