That's why I am so impressed with MiFi, an ultraportable WiFi hotspot recently announced by Novatel.
With MiFi, you'll pay a wireless carrier for a single 3G dataplan, then use it to connect whatever laptop or netbook you happen to be using. This will save me a ton of complexity. I have laptops that support PC card, and others that support Express, which means I can't easily use a single 3G datacard. And, I don't like having to launch the connection application. Simply switching on a WiFi hotspot will be much easier, and give me the added benefit of being able to share the connection.
By the way, having one of these in your backpack will provide a bonus benefit to iPhone fans. As you know, many iPhone functions are restricted to WiFi only connections. MiFi will give your phone a WiFi connection wherever you may be, using 3G as its backhaul. So you can download iTunes songs, for example, or watch videos on the Television app.