I personally detest modal dialogs, especially when modal dialogs are open and you can''t move all the modal windows/dialogs out of the way, to see required information, I think most modal dialogs are unnecessary and influence by laziness, tradition etc. not by requirements and usability.

You are also wrong about web pages, you can easily have non-modal dialogs, by using pop-up pages, I''ve found few cases where modal dialogs were really required.

This is not about technology at all.
Whatever is best for the particular business process, that is what must be built.
To generalize, saying that wizard-style interfaces are always best for data entry, is perhaps akin to ignore the finer points of just what kind of "data entry" and "transactions" we''re talking about.
Take example of insurance claims: the basic transaction is to save the new information into a new claim registration. However, during this a claim processor needs to
- check at some point that a policy is in force (aha, perhaps a new tab on the UI) and that its terms and conditions match the claim
- check at another point that premium payments are up-to-date (yet another tab to open in the UI, so that the payment history is visible)
- update at another point the customer data, perhaps even to record a complaint (one or two new tabs to open?)

Driving such a process through a succession of modal-only wizard windows drives claim processor nuts. I know because I''ve seen them in real life, operating both kinds of UIs. The ones that have a multi-window/tab environment are much happier.

My .02 euro on this one.

Regards,
Mihai