OK, so I have no first-hand proof of this yet, but there are certainly some promising features that we can expect with VS2008.
For me the main ones (for asp.net development) are:
Improved design-time support for CSS
Generally faster Designer
I am especially looking forward to LINQ, all to often I find myself spending hours writing repetitive data access code, time that I strongly believe could be better spent writing business logic elsewhere.
If it lives up to it’s promise, LINQ should make this a thing of the past and enable developers to write data access code much faster, but still maintain control over their code.
All in all VS2008 looks very promising.
For more information (and to download the Beta) take a look at Microsoft Visual Studio.