Hi Angelo,
I use an orginal Canon slim UV filter that doesn't cause vignetting and doesn't touch the front element. I believe these can be found on ebay every now and then, and they usually aren't very expensive.
The hood I use is an Olympus hood for the 55/1.2, which is a clamp-on hood like the the original Canon 50/1.2 hood and doesn't cause vignetting. I've had the original hood too, but I prefer the Olympus one. And it's cheaper too, if you can find one!
Lots of aftermarket screw-in hoods will cause vignetting on the Canon 50/1.2.