Cheap, gets the job done:
http://www.hobbypartz.com/thac6smbachw.html
Will do upto 6s lipo, 5amp charge rate, built in balancer, lots of great reviews, good customer support from Hobbypartz too. Limited to 50watts so if you charge larger than 3s packs it will take anything upto about 3 hours ( 6s 5000mah for example ), but for typcial 2-3s lipos you're looking at about 1-1.5 hours tops.
Cheaper options are available, but they either need a seperate powersupply, or lack features & adjustability.