I've been working with Windows Server 2008 since pre-release betas hit the TechNet download world. Initially, my focus was work-oriented, getting my job done. I had to deploy a few servers, and I found the overall structure to be the same as 2003, so I wasn't overly frustrated looking for new ways to do old things (like adding a simple user in Active Directory). Slowly, however, I became aware of some really nice enhancements within the latest Windows Server OS.
For example, there's Server Core. It has a command-line interface, a lighter footprint, and a smaller attack surface (making it a welcome security choice). It has read-only domain controllers, not unlike the NT 4.0 BDC (Backup Domain Controller) concept, but with a solid purpose of remote branch office domain controller deployment and without the security risk that a writable domain controller poses.
There's also RemoteApp Terminal Services. Why "TS" the whole desktop when an application is all your user needs? Yes, these features have me singing Windows Server 2008's praises.
And the forthcoming R2 (release 2) offers more. R2, as its name suggests, is filled with minor changes, but some are really interesting ones in the cosmic scope of things. For starters, R2 is being developed in tandem with Windows 7, so the two will work better together. In fact, certain Windows 7 features like Branch Cache and Direct Access will require R2 functionality. Group Policy settings for Windows 7 will be enhanced with R2 as well.
One of the nice new features involves Server Core, which lets you install a subset of the .Net Framework (2.0, 3.0, and 3.5) and thus install PowerShell as well. In addition, ASP.Net will be allowed in Server Core (again, thanks to the .Net Framework subset).
There are some Server Manager changes, such as the ability to perform remote management with Server Manager (which seems like that should have always been the case, like the Computer Management MMC, but it wasn't). There is also a great new server management tool called the Best Practices Analyzer, which Exchange folks will recognize as a great tool for scanning servers and reporting best practice violations back to the administrator. There are going to be a host of new cmdlets for PowerShell too, especially in relation to Server Manager to perform tasks at the command line (although the ServerManagerCmd.exe tool works well).