I'm a big fan of caching in ASP.NET
When you look at all of the .NET vs Java benchmarks it's usually the easy caching support that has given .NET the edge.

Andrew G Duthie has an article up on MSDN about the new caching stuff in Whidbey.

Specific goodies include:

• A non sealed CacheDependancy class. i.e. you can inherit and create your own dependency expiration rules.
• SQL invalidation. Obviously drawing from the above, there is now a bundled SqlCacheDependancy class. It looks like it is done via a polling mechanism rather than a trigger executed extended stored proc as used by Rob Howard in his example for use under 1.1 and 1.0
• Substitution capability for chaning content after retrieval from the cache.