I have cable internet on my trading computer and DSL on the surfing/backup trading computer. Here, cable has less latency than DSL.
Comcast Cable, $40 a month. Very fast, that test was from my out-of-date laptop, on a wireless connection, one floor down and on the other side of the house. I lub comcast!
I wouldn't be too concerned about your speed. I am a scalper and trade from Brazil. My down speed is just 1mb and my up is only 0.1mb. As pathetic as it may sound, I hardly get any slippage trading listed stocks. What really matters is your ping time to your order server. I get about 190ms avg in Brazil as opposed to 20ms when I was trading out of NY.
Cincy, OH Roadrunner. 39/mo Cable connection of course. My backup is a standard DSL connection for 19/mo. Never had the main go down, so never had to use.