Holy crap! I've just learned that Rockstar has put GTA2 up for free download as part of their "Rockstar Classics" series. So for all of you who never played anything before GTA3, it's highly recommended you go download this now! While most gaming sites like to ramble on and on about how GTA3 revolutionized the series, there's tons of great (and somehow overlooked) stuff in 2 which formed a basis for the San Andreas we play today. And then other things, such as the sheer ped and car density, even manages to trump the more modern 3D games.
Head on over to the Rockstar Classics page and have a go if you haven't played it before. Or if you've yet to experience the game in it native environment on the PC...