I googled this topic and I came across with three different ways to configure browser capabilities: browscap.ini, browserCaps element in web.config and .browser files in App_Browsers. I thought .browser files is the latest way, but I don't seem to find up-to-date files. But I found quite fresh browscap.ini from http://browsers.garykeith.com/downloads.asp.
My first priority is to exclude common crawlers from the visitor stats. The second priority is to detect browser and os with correct versions (e.g. Opera 11 / Win7).
Are there any libraries I could use? Is browscap.ini still a valid way and is it possible to use it without access to system files? Where can I find up-to-date .browser files?