I spent an airplane flight last week catching up on some MSDN articles. Three that I read related to Entity Framework and in particular EF 4.0. I thought they were well put together, actually discussing the issues involved with various types of data access patters and how they have evolved or been addressed by EF / EF4.
Building N-Tier Apps with EF4 is the third of the three articles and I think the most relevant (if not most important). One of the things I really liked was this graph showing the trade offs of the four primary data access models:
The article(s) go over these patterns thoroughly so I won't discuss here, but it's nice too see it quantified for once and to reiterate it.
The big part of EF 4 will be the concept of Self-tracking entities, which looks like a real panacea for many of the problems exhibited by the other three models. Again, this article goes into great detail on this so I won't repeat.
The other two articles in the series, both also worth a read, are:
Anti-patterns to Avoid in N-Tier AppsN-Tier Application Patterns
Cudos to Daniel Simmons for writing these.