I'd like to add that user specific file extentions be filtered out as well. An example would be *.mov files. I hate them and I have no use for them.
Plus, If I'm searching for a document, for example, and I'm searching for a *.prc file it won't list any. If I choose All Types, then I get a list of a ton of files that aren't even *.prc. So in Options just be able to add or subtract file extentions to search for and be able to add your own. Not just a list because who knows what kinds of files people want to share or search for specifically.
Or just in the Select Search Type window have either a drop down box of file types you want to search if you want to search for one file type only. Or a an input box to simply type the extention. This would kick ***!
Some people like things simple and ready made for them but I like to do it my way!