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:
ASP.NET User-Mode Output
vs
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 ScalabilityTODO: add more