Okay, I don't think I've logged in with less-than-admin privileges before now on any of my blogs, ever.
But, I just set up a test account on the RC1 build with "Subscriber" privileges. Looking at it from that point of view, there is WAY more information in the Dashboard than I'd care to expose to a new, naive user. (And by the way, this is not a criticism of the Dashboard in general--I think it's beautifully done and enormously useful.)
One could argue that the Screen Options tab at the top right can take care of that for a user, hiding stuff they don't need to see. And WP itself hides options they can't use in a more-restricted role, and that's good.
BUT--why expose all the modules in the Dashboard in the first place? I don't want a new user to be faced with such distracting tidbits as the WP Development Blog, the Incoming Links, and especially Other WordPress News--it's perhaps of use to users in higher roles, but absolutely confusing to some poor soul who just registered so they could add a comment or have their gravatar show up. (NO, not even that--the user I have in mind has no idea how to do a gravatar!)
Here's what I'd like to see in the core admin: a means to set defaults for the Dashboard for each role level. For example: I could decide that a Subscriber ONLY sees the "Right Now" and "Recent Quotes" blocks. The other blocks would remain available under the "Screen Options" tab, but I could choose to have them OFF by default for a newly-added Subscriber.
If it's too late to build this into 2.7 (and goodness knows it is! :) ), this might be a good plug-in experiment.
I'm proposing this because I think we don't "drop down" often enough--or ever!--to the perspective of people who are just trying out their first blog, and I think it's incumbent on the software to invite them in rather than intimidating them. Believe me, the Dashboard even in its simplified "Subscriber" state looks intimidating and even alien to a newcomer right now.