White Flood is popular because it really wires alot of people. Jack3d is known to do this as well. Ragnarok is a little less stim-heavy, but tastes quite nice (And comes with the option of being caffeine free). I am fond of JP8 as well, which doesn't get me as wired up at a low dose as other PreWO supps, but really helps with focus/endurance during my WO.
Too many great options out there
You can try out a WhiteFlood sample, that might be your best option. There's information on how to get the sample in the Controlled Labs subforum. You can also get a Universal Shock Therapy sample from their website; that one really lights you up; plenty of caffeine in there. Only take 1/2 a serving initially.