Web Browser Compatability

When doing a website, do you think it's right to be code for only certain browser (ie the most used browsers like Firefox & IE (latest ver)) and to just say to other users of browsers like Safari, IE 5 , "sorry you cant use this site"

I only code websites for browsers that are open standards compliant.

And I don't block off anyone or redirect them to a browser download page, that's just being a dick.