* I use it as a music player. I have several playlists. Some I made like "Songs I don't own" "Older songs I don't own". Some others made and update like "Maximum Decibels" and "Hard And Heavy" - a way to find new music. Some are albums I don't own (playlist containing each song in the order of the album).
* I watch TV shows. I've watched every episode of Three's Company, IT Crowd, In Living Color and more. I've watched a ton of old and new Whose Line Is It Anyway, and also Drew Carey's Improv-A-Ganza.
* I watch movie trailers, new and old.
* Even though most music videos suck, I keep a playlist of the good ones.
* It's a resource for finding stuff you've seen and want to show others (I showed my wife "Who's On First" last night, and I've shown my son all of the Mel Blanc Spanish guy scenes from Jack Benny's show where he says "Si" a lot, and I posted Weather With Al on here a little while ago). And stuff others mention that I want to see (a friend said I'd like a scene from a Young Sheldon episode, so I looked it up and watched it). And stuff you haven't seen in years (I saw a documentary about Nostradamus when I was a kid that gave me nightmares. I found it on YouTube and it was interesting to see how tame it seems to me now).
* Educational videos. My favorite channel is CGPGrey. When my son was younger, we'd watch Brusspup videos together (optical illusions and fun science).
* Stuff that makes the news. Like Stephen Pearcy, Layne Staley and Vince Neil bombing on stage, for example. When I see a headline like
Ratt Fans Boo as Stephen Pearcy Struggles Through Another Show I want to see the fan footage of it. Usually that stuff hits Twitter first, then YouTube.
There's probably more but that's likely the bulk of my viewing.