One other thing to consider is the 100 skill perk for each armor type. Heavy has the perk that gives you a chance to have damage dealt to you reflected back, which is ok, but i personally would rather have the light armor perk with gives you a chance to completely dodge an attack.
Why would you want a 10% chance to just avoid damage when you could have a 10% to completely reflect it?
There are a lot of misconceptions being thrown around here:
First, you regenerate stamina much slower in combat (about 1/3 of the normal rate) so that +50% increase will not be as noticeable in combat as it becomes +50% of that 1/3 rate.
Second, both armor trees have a weightless perk so that's a moot point.
Also, people seem to be disregarding that 50% less chance to stagger perk in the heavy armor tree. That's an effect you can't duplicate with an enchantment, unlike the stamina regeneration light armor perk.
Basically, if you're going to be stealthy at the start of the game, go with light armor. If you don't plan to be stealthy at all or plan on doing it much later in the game (with the Muffled Movement perk from the sneak tree) go with Heavy. Though you may still find sneaking more difficult with heavy armor than with light even with Muffled Movement but that's okay because you'll probably be doing most of your sneak attacks from range.
*Edit: Also, Also, power attacks done at 1% stamina aren't doing any more damage. You're just doing a slower normal attack. Power attack damage is proportional to the amount of stamina you have available.