Ah yes, I had this curious question too and the deal about T-Mobile Email Only is just that - it covers as many email accounts as you can sync, be it POP3, IMAP, Hotmail, Exchange... $9.99 will keep you covered. They this option is applicable to the newer phone as when one opts for that service, then Web access is actually blocked.
As for T-Mobile Web - it is WAP service, so don't expect any miracles of being able to connect to some of the richer web content. In fact, when you connect using WAP (on the Shadow), there's a flashing "W" indicating that method of connectivity.
Total Internet is just that - all methods of data connectivity EDGE, GPRS, Email, Wi-Fi (yes you will have HotSpot access on or off your phone) all for $19.99!
- yes Mike, I've sidelined my Dash for the Shadow... at least for now
