If your serving up static files, like your virtual earth JavaScript files and your using IIS6 then you should know about kernel mode caching. The basic idea is it's the fastest cache, new to IIS6, that can serve your static pages very early on in the stack.

from Mircosoft:

The difference between user-mode and kernel-mode output caches for ASP.NET pages.

	ASP.NET User-Mode Output Cache	Kernel-Mode Output Cache
Requests / Sec	1,394	15,416
TTFB / TTLB (msec)	70.82 / 70.97	3.39 / 4.02
User Mode CPU %	76.57%	0.78%
Kernel Mode CPU %	22.69%	99.22%
System Calls / Sec	20,110	2,101
Network Util (KB / Sec)	6,153	68,326
Context Switches / Sec	2,621	6,261

Check out the following resources:

Web and Application Server Infrastructure - Performance and Scalability

TODO: add more