If you're hosting the .NET Framework 3.5 (Beta 2) or planning on it, keep in mind there is some additional work required for the Beta 2 bits. The attached document describes two issues (and their corresponding workarounds) when hosting ASP.NET websites...
One thing you can do to help save memory usage is to enable the WorkstationGC. The GC, or garbage collector, manages the memory for appDomains. http://support.microsoft.com/kb/911716