It depends who you are speaking with. If it is business, then usually Regards or Kind regards (more friendly). ('Yours sincerely' would be rare unless it was very formal or legal. 'Best wishes' is usually for people we know fairly well. 'Warmly' and 'Cheers' are fairly low key and friendly. 'Take care' would normally be for friends and maybe family. If someone is above me in my job, then I usually copy their sign-off.

I use “regards”more often. But I agree that it depends more on your own situations.

I believe it's really up to who you are sending an email to. I use 'Regards' as my standard email sign-off.

i would use yours truly then yout name