Microsoft also used to accept BTC.
Microsoft still accepts bitcoin in the present day.
They do have some restrictions:
You can only use Bitcoin to add money to your Microsoft account and then purchase digital goods at select Microsoft online stores. You cant use Bitcoin to purchase Microsoft products and services directly at this time.
But other than that, they are still actively accepting bitcoin.
In addition to the sites already mentioned,
Namecheap is a domain registrar accepts bitcoins.
In addition, you can obtain most gift cards with bitcoins through gyft or some other site, and use those to buy the services you need.