The Dick Wadd piss scenes (particularly Soaked) are the ones that make me feel like I am living in the Sahara.
Jalif's Kings of Piss is also choice.
If you have the stomach for it, no one does piss quite as good as the heteros from Eastern Europe. There's a whole series and the title escapes me at the moment but serious fucking golden showers! Extra hot is a scene where one guy accidentaly pisses on another guy and then it turns into an out and out piss fight between the two of them and they ignore the skanks for a bit. Not just one of my fave piss scenes but one of my hands down fave porn scenes.
What I don't notice in most piss videos but is one of my favourite sensations when I am comfortable with a guy is having the piss fucked out of me (preferably we do this anywhere but @ my place).
There I go sharing too much again, just call me Napster.