Here's a great thread on this topic. It hasn't been updated in about a year and a half but is still valid. My top five from the list are:
1) Famous Nic 5000 Toro. From Famous Smoke Shop.
2) Ramon Bueso Genesis the Project Robusto. From Cigars International. It's on sale several times a year for <$3/stick.
3) Gran Habano 2002. Many online sources.
4) Diesel Unholy Cocktail. Many online sources.
5) 5 Vegas Series 'A' Anomaly. Can be had at CI for <$3/stick quite often.