Do some searching on here.....this has been answered 1000X before.
But if you're lazy, here's MY opinion. Ask 100 people, you'll get 100 different answers.
If it was me, I'd be going straight to Sannies Shop and buy something from him or Eskobar (Breeders Choice). For the money, there IS NO BETTER. Period.
That being said, I've ordered from Attitude, maybe 15-20X and have gotten every order. They can guarantee delivery, so make sure you pay the extra to get that deal for piece of mind.
Good stuff: Dinafem, Sweet Seeds, Connoisseur, TGA, DNA, Reserva Privada, DJ Short, Gage Green, Paradise, Serious, Mandala
Bad stuff: Barney's, BC Bud Depot, Flying Dutchman, G13 Labs, KC Brains, Nirvana, Reeferman and of course, Dr. GreenThumb (his beans are only available on his own website).
The above reviews are from my own personal experience. Much of it depends on strain selection and not all my choices have been smart/proper/easy/thought out well/etc. Pot will do that to you sometimes. Do some searching here and you'll get a better feel for what direction you should head towards....