If you're cruising the states get an Aircard from your mobile supplier. If you go offshore and foreign then a wifi will be good. We were frustrated with wifi in the states. I have a WaveRV Marine antenna and the number of secured ones seemed to just create a lot of SNR. And I think the suppliers are happy to show people how to secure them so they can sell another act!

Out of the states you need an wifi antenna. I'm using the WaveRV but consider is only OK. Haven't talked w/ anyone that has found the magic bullet. Most of the high gain ones work on B/G but not N. An up and coming down side.

Good luck, There ain't no great solutions.

Fair Winds