I've been landing some pretty good Nevermores with Swain. Laserbirding anyone trying to run away is fun, too. Then once you pick up a Rylai's, just dance around a team fight in Crow-form and you've pretty much made sure no one escapes (well, if your team cooperates).
Ashe is pretty good, too, at keeping enemies crowd-controlled. Volley with Frost shot is pretty annoying when you're trying to chase or are being chased. Then her Ult flying across the map can definitely screw up a gank or backdoor.
Zil, Singed, and Lux also come to mind when I think of cc.