I liked 3DO's website. It had really cool strategy guides and tips and information I have not been able to find out anywhere else on the Internet (I mean, those exact guides, the information itself is scattered through other materials). When the company went under, I still didn't have stable Internet connection, so by the time I realised I had to fire up the ol' modem and go salvage whatever I can from there, it was gone. Such a shame.
I don't think I have anything else "old" I enjoy. There is GameFAQs which is the oldest website I've consistently been a member of and visited over the years. It was one of the websites I visited every time when giving the 56k a spin.