Through hours of browsing and having discussions about Nostr on the web these last couple days, these are my favourite services so far:
https://coinos.io/ -- I love the simplicity of this wallet. It doesn't ask for anything upon sign-up, an it works very well.
https://nosta.me/ -- It's like a "Beacons" Web App which gives you all the necessary information about your resources in front of you. Nosta has been extremely helpful for me. I would use a service to try to configure the things I configure on Nosta, and they would mainly give me hell by not changing, or not staying enabled. Nosta is so much better than those "Beacons" apps.
https://habla.news/ -- A longform blog-centric use case. I like the feeling of it because unlike Medium, it doesn't ask for Stripe, and with that, the underlayment is totally different because it doesn't want you to be a "commercial" entity if you want to receive any sort of profit(lightning). Fuck all that.
https://jumble.social/ -- A great micro-blogging, #shortform platform. It reminds me of older iterations of similar things. Not the Blue Bird, and definitely not the whale or the butterfly! We got the #nostrich, baby.
https://nostirc.com/ -- It is Internet Relay Chat on a Nostr instance. You are verified by your key, and has been a smooth ride so far. Join #introductions on #Nostirc. It will work with your favourite IRC Client as well. The people are rad.
https://stacker.news/ -- Pretty new to this platform, but it is like #reddit but totally different. It looks be be heavily lightning-centric. I can't wait to dive in more.
https://nostr.net/ -- An amazing web store for #Nostr that I'm sure most of you know about. I think it was one of the first things I went to when I joined Nostr.
If you know of any more cool services, please let me know with a reply! Some #lightning would be rad as well!