Whats the best internet service for an xbox 360?

i live in Stuart, Florida and im looking for a always green connection. there are 3 computers in my house, mine on ethernet cable, second wireless, third is a laptop wireless. (that's what takes my connection). i want to be able to have him on and me not lag out of any games. I currently have At&t, and they were good until the laptop took my connection. Please help and be specific.