It really depends on the map and the match, and what I scout, but I've used the technique to good effect in many of my matches. In fact the hellions pre-igniter or otherwise are not that effective against IT, they're very effective against melee light-armored units but against range light-armored units they require more focus micro to pull it off, not to mention they're rarely used during the mid to late game. They're good for harrasing expansions especially on larger maps, but by then a Terran player has so many other units available. As for Siege Tanks, this is one of the spells use constantly when I'm against Terran Mech or Tank/Mass bio as Zerg, toss out IT eggs into the Siege lines and watch the fireworks (Also Siege Tank damage is being nerfed next patch). Yes the Colossus is very effective, but by then I'll likely have corrupters or mutalisks out and Neural parasite researched (This depends, I usually have a spire before I get the Pit, but again, this really depends on what I scout out, usually I go more of air army if I see Immortals or Colossus on the field, and harass the fuck out of him). As for Psi Storm, personally I feel it's a waste to use storms on Infested Terrans, but that's just me.