If we have a voiced character in F4, I would love to see their voice sound muffled when they speak wearing Power Armor. It'd be so cool. It's supposed to have that 'walking tank' appeal but it just didn't do it for me in F3. I used the T51 from Operation Anchorage because it offered better stats and the appearance was a lot bulkier, making it look very plausible. T51 Armor and a Gauss Rifle done it for me.
In NV, it was somewhat difficult to get, but generally, I usually wore faction armor (usually the side I am siding with, if it's CL or NCR). If it ain't those two, I just usually wear travelling gear.