If you are looking for a file by name, and don't want to use Spotlight's File Name button, just press and hold Shift, select the Finder's File menu, and notice that the Find entry has become Find by name.
Select that entry, and the Finder will open a new window with a preset search set up for Name Contains; type your filename, and you're done.
[robg adds: You'll see a bit of a visual bug when you do this: the search dialog will have Contents, not File Name highlighted, and then the Name Contains line below that. So technically, it seems you're searching files whose contents contain a file name you specify. Clearly that doesn't make any sense. In any event, it seems Apple heard the complaints about easier filename searching. You can take the shortcut to this solution by pressing Shift-Command-F, or you can just type name:somefile or name:"some multiword name" into the Spotlight search box.]

