I honestly don't even bother washing the yeast. I pour off most of the trub, yeast, and whatever else is in my primary fermentor into a sanitized ball jar. That jar goes into the fridge for a week or two. When I'm ready to use the yeast again, I pour off the beer that is on top of the yeast, give it a good shake, and toss all of it into a starter.
Bottled: Oatmeal Porter, Double Chocolate Chipotle Porter
Kegged: IPA, Red Rye