Sure they are, but they drain the battery at different rates depending on what they're doing. How much of a drain is it to have such wireless interfaces fall back to an 'idle' state?

Nokia's own mission is to have an 'always on' device that lasts you a whole day (by which I take it to mean a 'working day' - say 10 hours)

If I have an app that wakes up periodically and polls some network service, will the renegotiation etc involved with reinitializing the network interface each time, actually prove to be more troublesome?

I don't know the answers to these questions....I'm just curious