i think the interval really depends on the person and how you drive. thats my personal opinion.
i was doing the long life service, mainly because id have nothing to pay for every other year, but then realised that it would be more beneficial to get it serviced more regularly.
im currently going to get mine serviced, ie oil change, oil filter, fuel filter done every 5000-8000 miles or so. maybe over the top to some people, but i intend keeping my car for a long time so want it to be running as best as it can. i dont really pay much attention to the service light, tending to reset it as i know when it needs doing. i think it really acts as a reminder rather than YOU MUST SERVICE ME NOW!!! type of thing. id just reset it again.