I'd have to go with PokerStars. Each day with 4 PokerOwned Freerolls, 6 PokerSchoolOnline Freerolls, 12 Freerolls from other sites, and 6 Sattellite to the monthly 2000$ Freeroll, you get decent amount of play for free.

And on top of it, if you follow training sessions and such on PokerSchoolOnline, you get awarded some free tickets to many tournaments almost every week.