Favorite obsolete formats.....

78 rpm.  Much of America's best music can be found in this format.  Not obsolete for me!

R2R, cassette and (FM) radio still very much alive here.

Blankets with fringes and tassels, more info, revealing to the bone.
I used to have also cans with strings to communicate with the neighbour, great times.

bell bottom jeans (on certain body types, thank you...)   :)

MiniDisc and Hi-MD.

My dislike of certain magazine reviewers reached near pathological levels as I used to read one disparaging review after the next. 

It was that word 'lossy' that they all, to a man, latched onto.

Yet I would bet that not a single one of them paid profiteering prejudiced shills could unsightedly distinguish between a MD recording and the CD/vinyl/ hi-res original.

As a result of their unceasing negative propaganda we lost a wonderfully versatile recording / compilation medium.

Instead of serving their readers many of these goons continually seek to exploit them. 

Worst of the current bunch? Darko and What Hi-Fi are the two that immediately spring to mind.

Sorry, I got just a bit triggered there, but it still needs saying and repeating.