ew. I don't bar anything unless I have to. I play them with my index, ring, and pinky. it's alot more comfortable, and when you play the kind of music I do where power chords make up a majority of everything you play, being comfortable is important otherwise after two songs you're ready to quit. plus, if you're writing music with power chords in it, that position makes it easier to do variations of power chords to keep your music interesting. for example

D|-3--3--3--3----3--3p1-1---
A|-3--3--3--1h3--1--1---1---
E|-1--1--1--1----1--1---1---

I dunno, that was just an example I just made up... but you get the idea. if anything, the first finger is to be barred for me, then my other fingers can move around and create variation