Every other Fallout game, I've played with Power Armor and Energy Weapons. Plasma Rifles remain the best ever. I much prefer the look of the Plasma Rifle from Fallout 1 & 2, though. It looks so intimidating. I even did that first time playing through Fallout 3.
But on my second character, I did something quite different, and quite enjoyable. I can't remember the exact skills and attributes, but I based my character on Small Guns and Stealth. Used the Ranger Combat Armor exclusively from the moment I got it. Damn, playing through the Ranger quest was intense on highest difficulty. Running out of stimpacks a quarter in, and ammo about half-way, things got really interesting. Having to kill super mutants with nothing but a combat knife is quite satisfying, both because they're awesomely big and the knife is tiny, and because having to resort to a knife because you have to conserve your ammo adds a certain realism. Can't wait for New Vegas for even more realism.
The Pitt really makes such a character easier to play, too, adding the Infiltrator / Perforator. I think those are the right names, anyway. Rifle with a suppressor. It's not quite as powerful or amusing to use as the Lever-action rifle from Point Lookout ( best DLC for Fallout, by the way. ; D ), but it works really well.