Check out garagejournal.com for lots of lift threads. I've got a Bendpak 4 post and like it because it can be moved, came with a air/hydraulic sliding bridge jack (lets me get one end in the air), useful for storage and no arms in the way like a 2 post. The bridge jack makes a big difference for maintenance although you can slide an aluminum floor jack under the lifting points of newer cars if you need to. Its not cheap once you add the bridge jack.
A 2 poster is nice but is bolted to the floor. The posts are rather far apart which does cut into the usable width of the garage just the same. It also takes longer to get the car set up for a lift. The suspension will hang if you use it for storage and there are no drip trays.
Each has its pros/cons so you have to figure out what you will be using it for. Either way, you need 11 foot ceilings if you have a sports car and 12 foot for a Mopar and more if you want to put a truck or SUV under it. That is assuming you would like to be able to stand up under it.