Bear in mind this is a gross oversimplification. The general things I read are:

Light armor is best/mandatory for stealth. If you're not going to hide, choose something heavier.
Chain armor is the best match up of low hindrance and good protection. It can be crafted to have as low hindrance as leather, or as high protection as (low) plate.
Brig has no place. It's a TDP mill.
Plate is only usable for Paladins, once you reach higher levels; at higher levels the penalties to evasion/etc. outweigh the protection it offers, leading to increased wound count and severity.

That said, I tend to favor a mixed set for my low level characters. Especially clerics, who have level 1 access to mpp. I prefer chain on the torso and head (shirt and balaclava), brig on the hands, and light armor on the legs. I really do avoid plate.

>Eh, Plate is only for paladins, but they can wear it pretty easily pretty quickly.

Plate is only for Paladins once you reach high levels. More accurate way of saying that, sorry. Paladins can (and should) wear a full suite of mixed armor out of the gate. What would put most people at a 13 hindrance puts a Paladin at a 6 (it's instant, as soon as you join the guild, I've tested. No guild, 13. Type 'join', 6)