I am learning so much since getting my iPad four days ago. Now, which is faster, WiFi or 3G. I know we pay for the 3G, so I'm thinkin I just answered my question... Or not?
There's a free app called Speedtest in the app store that will let you compare speeds over a 3G connection and a WiFi connection.
It'll depend on your internet connection, but generally wifi will be faster. If you have a very lousy/slow DSL line, 3G might beat your wifi... after all your wifi is only as fast as your internet connection is.