You don't necessarily need to generate card advantage (although Trinket Mage draws you a card!). This is a dirty dirty myth I see propagated all over the place.

Aggro_Zombies: Is 4 4-drops too many at that point? I'm worried about fanning open a hand and having to mulligan because it has 2 lands and two Jaces and a Humility and a Top or something.

4 Top is a myth. Yes, you can tutor for it, but if you want to CB lock them out on turn 3, you pretty much need Top on 1, CB on 2. Tutoring up Top ruins this plan, especially if it's turn 4 from a Trinket Mage. Plus, you don't ever want to have to use E-tutor on a Top, although I've done it.