Good point Xena about the obj files...very important.

Another note on weather to "conform" or to "parent"...if say you are making some chest/shoulder armour and you conform them, if you modeled your armour with hard rigid lines...when you conform it your hard lines will bend and whatever textures you have will also bend....depending on what you are after this is sometimes very bad effect (the armour stops looking like armour and looks more like a skin tight suit).
Really the only way to understand what I'm talking about is to try it yourself and you'll see.

So with that in mind if you are going to parent it, then when you model, keep in mind to stay close to each body parts limits so that the parenting won't look real goofy. Otherwise if you go past your body part limit and extend your parented chest model into the shld area (for instance) the ends will really start to cause some havoc.
Very bad if you are animating, not so bad if you are just taking single frame renders...minor fidgitting with the prop will align everything okay.

Hope this helps.

Comitted to excellence through art.