DigitalOcean is a great hosting service. Even if I host my persoanl websites as static pages, whenever I want to do any web development that requires a cloud-hosted backend, I fire up an instance at DigitalOcean (and it's up in a few seconds!).
Their pricing is very good, they use SSDs on all their machines, they offer great bandwidth, they have an API... OK, you get the idea.
Use this link to sign up for DigitalOcena and get a $10 credit.
(That's two months free for their entry-level instances.)
I use Hover to register most (probably all, but I'll have to check to be sure) of my domains. For me, they are the best: They stick to what they do great, and they don't try to cross-sell various other "products". I also like them because they offer "whois privacy" for free, which is a feature I always use but I had to pay for it in other registrars.
Backblaze: The best cloud-based backup I've used. I've installed it on my Macbook Pro and on my wife's iMac and I can be sure there will always be a backup of our data in case of a disaster. And you don't have to do anything, just install it and it will keep backing up your computer in the background.
I've been using it for years and I couldn't be happier.
OK, I know that almost everyone knows about Mailchimp, one of the best email marketing platforms around. I use it to send my newsletters and I've been using them for years for personal and professional projects. I can't recommend them enough!
If you are not a user already, use this link to get $30 in MonkeyRewards.