What type of Jeep to you have?
For a YJ, I'm pretty happy with my Rubicon Express 4.5 inch extreme duty lift. It comes with just about averything you might need, drop pitman arm, greasable shackels, extended brake lines, etc. You may also have to install a slip yoke eliminator and a rear CV driveshaft but you might be able to get by with the transfer case drop (included in kit) for a while. Also, you will need to get some shocks since they are not included in the kit.
Gear ratio is 4.88, general consensus.