Ragavan, Nimble Pilferer [c]Ragavan[/c] is one of the most powerful one-cost creatures in MTG
For example, if you play a deck that includes black, white, and red spells, a land like Nomad Outpost is a good solution
While it hasn't made too many waves in the tournament scene (although for a brief, glorious moment before Reflector Mage was banned, people were playing it at the Grand Prix level in Standard with some success), it's one of the best "build around" cards in both Standard and Modern
Still need to get my hands on the creature token.
Exile removal effects are more useful currently as well
The Infiltrator has a few subtle disadvantages to his snake cousin: 1) You need to play two colors to play the Infiltrator, instead of one for Ophidian