Harry McCracken, who certainly knows a thing or two about this topic, has a list of the Twelve Greatest Defunct Tech Magazines Ever. I do miss the sass of MacUser, I do remember the fun stuff in Computer Gaming. I would also add BBS Magazine to the list -- I loved them because they never talked down to their readers...
Open question: where's the similar list for online sites and blogs that might not have gone out of biz, but are no longer recognizable? For example, I'd say Wonkette was never the same once Ana Marie Cox left. Others?