I don't think I'm spending less time on the pc or laptop. But I'm certainly spending more time browsing on the phone than I ever did before, especially in the wee small hours. In fact, n900 has cured my insomnia: instead of lying awake worrying about stuff, getting tense and not being able to go back to sleep, I spend half an hour checking email/twitter, browsing and maybe playing a game or two, then roll over and sleep.

N900 - better than zopiclone.