What's some technology of the past that you wish you had?

A CRT monitor. The only way I can see myself using a dual monitor set up instead of just using "multiple workspaces/virtual desktops" on one monitor is if I had a CRT for old shows/movies and a HD monitor for everything else. My computer case even has a separate port for a VGA monitor, so this is entirely possible.
I too miss iDog like someone else here.
I also wish I had a CRT TV just for VHS & my broadcast TV antenna, and that broadcast TV didn't switch to "digital streams" over analog. They only play reruns of older shows and the news. I think it'd be fitting to watch Columbo or Looney Tunes or what have you on a CRT. Plus the digital streams are obviously an excuse to make broadcast TV "DRM" WHICH SUCKS BIG TIME!!! They didn't care when people were recording TV shows on their VHS tapes because then it was an excuse to sell other tech. Meanwhile if someone rips media off their TV digitally, it's seen as a "big deal" for obvious reasons. But of course, they say the digital broadcast TV is for "better quality" and maybe sometimes yeah. But when it has a poor signal, it's so pixelated and quite frankly, a lot of people are nostalgic for the grainy TV look, myself included.