It would be nice to have a more or less complete list over what files and/or directories that shouldn\'t (in most cases) be under source control. What do you think should be
The best way I've found to think about it is as follows:
Pretend you've got a brand-new, store-bought computer. You install the OS and updates; you install all your development tools including the source control client; you create an empty directory to be the root of your local sources; you do a "get latest" or whatever your source control system calls it to fetch out clean copies of the release you want to build; you then run the build (fetched from source control), and everything builds.
This thought process tells you why certain files have to be in source control: all of those necessary for the build to work on a clean system. This includes .designer.cs files, the outputs of T4 templates, and any other artifact that the build will not create.