I think the "Fun-ofs" are great! I have a couple of slots available in my list, and I often play some "gotcha" singletons in there. I rotate them around just to keep people on their toes. I'm currently using the slots for a second Toxic Deluge, a Collective Brutality and an Inquisition of Kozilek - going with the redundancy plan. I've used Shadow of Doubt, Surgical Extraction, and Imp's Mischief before. I really like Shadow of Doubt. I've tagged Stoneforge Mystics, Intuitions, Green Sun's Zeniths, Gambles, and of course a billion fetches. My White Whale is getting an Imperial Recruiter :) I think they all have their uses, and choosing one or 2 slot based on what you think you might face or what you are worried about is just fine. Chances are it'll just be pitched to a Lili anyways.... I'm currently anxious about losing to Jace the Mindsculptor, so I'm considering a pair of
To The Slaughters in those spots.