I've got a feeling that most of us have forgotten the base address for dll:s when .NET arrived. Back in the VB6 days I guess at least some of us did set the base address, but for the same reasons as back then, it's worth setting the base address to something else than the default 0x400000 (&H11000000 for VB), at least for reusable assemblies. The setting is a little bit hidden, but you can find it from Project Properties -> Build (Compile for VB) -> Advanced.

So, how do I know what value to set the base address too? Well, one easy way that I use, is too look at the properties of a dll in an application like Process explorer (from sysinternals) and then use the address where the dll is loaded as the base address.