The initial estimate is likely to be similar between an Agile and a Waterfall project, simply because you have the same amount of information (=not much). The most important difference is that the Agile project enables you to continuously refine that estimate, and therefore to actually *manage* the project, whereas being late with a Waterfall project is often only noticed when it's already *too* late to do anything about it.
The soul is dyed the color of its thoughts. Think only on those things that are in line with your principles and can bear the light of day. The content of your character is your choice. Day by day, what you do is who you become. Your integrity is your destiny - it is the light that guides your way. - Heraclitus
Well, i personally think that developers shouldnt set the targets. Its for the manager to do it, be it Agile or Non-Agile
I agree, with Ilja Preuss, that for Iteration 1 the estimates should be the same. In Agile model, its iterative dev, and estimation is more complex. . in non-agile model, there are standards available to size the new requirements added / changes to exisitng functionality. One example is Function point technique, which could be used to esimate dev and application value addition services