I'll at least chime in with the things I do on my Apple Watch. I've had it since launch (so about 1.5 years) and I've worn it every day. Here are the things I use it for in decreasing order with the number times I use it for that activity daily:
1. Time (might be obvious, but I didn't wear a watch before this... so I really didn't know if I cared to have the time on my wrist. Turns out it's crazy convenient!)
2. Weather. I have the current temperature, the forecast for the next 6 hours and a notification when it's going to start raining. Using "Time Travel" (you can spin the wheel on the Apple Watch to move forward or backward in time) it's easy to get a quick look at what weather is coming up later in the day or tomorrow.
3. Notifications. Takes some tailoring of what apps are allowed to notify you on your wrist, but once you get it right it's indispensable. I have Google Inbox setup to only ping my wrist with really important emails and the MLB app setup to only forward important notifications about the Red Sox to my wrist (like the game is starting and if the score changes). Too many notifications and you just ignore it... you have to get it just right.
4. Messaging. It really is convenient to get texts on my wrist. If the message warrants a quick reply then I do right from my wrist... if not, then I can decide if I need to pull my phone out to answer.
5. Phone calls. Not necessarily answering them (I don't usually like to talk on speakerphone) but it's pretty insanely useful to just glance at your wrist to see WHO is calling before deciding to either dig your phone out of your pocket or run across the house to get your phone.
6. Calendar. Instantly shows when my next appointment is. One touch shows me my calendar for the day.
7. Bus arrival time. I have a great App that shows me when my bus is due at my stop. I fire it up every morning and leave it on while I get ready... every time I raise my Watch it refreshes the time for the bus so I can keep an eye on it while I get ready.
8. Setting Reminders. You can add new reminders just by raising your wrist and saying "Hey Siri add Milk to my grocery list" or "Hey Siri remind me tomorrow morning to call the Vet". Super useful when you're walking through the city and you think of something you need a reminder for.
9. Using Reminders as a Grocery List. I use an app called "Reminders Nano" that shows my Reminders on my Watch. I open it up before I go in the grocery store and it shows me all of the things added by #8 in my grocery list... as I pick them up I mark them off on my Watch. Works great without having to fumble with a phone with the shopping basket.
10. Activity tracking. This one is straightforward. Even though I use it every day (and meet my goals everyday) I put it as #10 since it's really more of a background activity for me.
11. Apple Pay. I pay for things daily with my Watch. Not yet ubiquitous so it's not higher on the list... but it does get used daily for that purpose.
12. As a ticket. It's great to have Passbook Passes (airline tickets, concert tickets, stadium tickets, etc.) right on your wrist. I really love using it while flying... one less thing to have to fumble around with when you're trying to wrangle baggage...
11. Control my Nest. There is a great app called "Thermo Watch" which is extremely high quality and is used to control the temperature setting on your Nest.
I do a lot of other minor stuff with it... but those are the big ones. Is it "life changing"? Absolutely not... but it was definitely worth the money I paid for it. I use it far more than other things I've paid WAY more money for.