Magic's Modern format has a rather large card pool, including 90-ish counterspells with a good variety of mana costs and limitations. Assume you're playing a control deck that can fairly reliably take over the late game, but really wants early disruption to get there, as well as occasional protection for your big controlling power play (whether it's a combo, a powerful fatty, or just a wrath to buy you more time). Given the constraints on counterspell power represented by the Modern set, which of the counter cards available make the strongest inclusions for early-turn defensive play, and why?
(I scoped this question to Modern because it's an "eternal" format with many options but no access to the early-edition uber-counters like Mana Drain and Force of Will.)