According to Steven Sinofsky, senior vice-president of the Windows and Windows Live Engineering Group, there will be no roles on Windows 7. With Windows Server 2008 role usage, we've all assumed roles not to be discontinued, but according to Steven, "We’ve seen scenario or role-based setup as a very popular feature for Windows Server 2008. In the server environment, however, each of these roles represents a different piece of hardware (likely with different configurations) or perhaps a specific VM on a very beefy machine, and also represent very clearly understood "workloads" (file server, print server, web server).
The desktop PC (or laptop) is different because there is only a single PC and the roles are not as well defined. Only in the rarest cases is that PC dedicated to a single purpose. And as Mike in product planning blogged, the reality is that we see very few PCs that run only a specific piece of software and in nearly every study we have ever done, just about every PC runs at least one piece of software that other people do not run. So we should take away from this the difficulty in even labeling a PC as being role specific."
I'm glad Microsoft (Steven) is choosing priorities. I believe Microsoft is placing a good bet here, by getting the out-of-box experience for Windows 7 just right.