Best – This is the most ubiquitous; it’s totally safe. I recommend it highly and so do the experts.
Best – 是最普遍的；绝对安全的。我和专家都极力推荐这个。 (来源：英语学习门户网站EnglishCN.com)

My Best – A little stilted. Etiquette consultant Lett likes it.
My Best – 有点生硬。礼仪顾问Lett喜欢这个。

My best to you – Lett also likes this one. I think it’s old-fashioned.
My best to you – Lett也喜欢这个。我认为它过时了。

All Best – Harmless.
All Best – 用起来无大碍。

All the best – This works too.
All the best – 这个也管用。

Best Wishes –Seems too much like a greeting card but it’s not bad.
Best Wishes –看起来特别像贺卡，但是还不赖。

Bests – I know people who like this but I find it fussy. Why do you need the extra “s”？
Bests – 我知道有人喜欢，但是我觉得它很繁琐。为什么你需要多余的“s?”

Best Regards – More formal than the ubiquitous “Best.” I use this when I want a note of formality.
Best Regards – 比最普遍的“Best”更正式。当我想要正式的写结尾时我会用这个。

Regards – Fine, anodyne, helpfully brief. I use this.
Regards – 好，稳重，简短。我用这个。

Rgds – I used to use this but stopped, because it’s trying too hard to be abbreviated. Why not type three more letters? OK if you’re sending it from your phone.
Rgds – 我过去常用这个但是现在没用了，因为这个很难被缩写。为什么不多写几个字母？如果是用手机发邮件的话，这个OK 。

Warm Regards – I like this for a personal email to someone you don’t know very well, or a business email that is meant as a thank-you.
Warm Regards – 给不是很了解的人发私人邮件时我喜欢用这个，商业邮件中它的意思是谢谢你。

Warmest Regards – As good as Warm Regards, with a touch of added heat.
Warmest Regards – 增添了一丝温暖，跟Warm Regards一样好。

Warmest – I use this often for personal emails, especially if I’m close to someone but not in regular touch.
Warmest – 私人邮件中我常常用这个，尤其是当我离别人很近但是又不常联系的时候，我会用这个。

Warmly – This is a nice riff on the “warm” theme that can safely be used among colleagues.
Warmly –这个一个关于 “warm” 的主题的很好的结尾，在同事之间使用很安全。

Take care – In the right instances, especially for personal emails, this works.
Take care – 在适合的情况下，尤其是私人邮件，这个很有用。

Thanks - Lett says this is a no-no. “This is not a closing. It’s a thank-you,” she insists. I disagree. Forbes Leadership editor Fred Allen uses it regularly and I think it’s an appropriate, warm thing to say. I use it too.
Thanks - Lett说这个禁用。他认为“这不是结尾而是感谢。”我不同意。福布斯编辑领导 Fred Allen经常用这个，我认为它是一个合适的、暖心的词。我也用。

Thanks so much – I also like this and use it, especially when someone—a colleague, a source, someone with whom I have a business relationship—has put time and effort into a task or email.
Thanks so much – 我也喜欢这个，并会用这个，尤其是当某人—同事，人脉资源，跟我有业务关系的人—花时间和精力完成任务和邮件时，我会用这个。

Thanks! – This rubs me the wrong way because I used to have a boss who ended every email this way. She was usually asking me to perform a task and it made her sign-off seem more like a stern order, with a forced note of appreciation, than a genuine expression of gratitude. But in the right context, it can be fine.
Thanks! – 这个很让我恼火，因为我曾经有个老板每封邮件都用这个结尾。他经常让我完成一个任务，带着勉强感谢的符号，这让他的结尾看起来像是一个严厉的命令，而不是真诚地表达致谢。但是在合适的语境中，它也适用。

Thank you – More formal than “Thanks.” I use this sometimes.
Thank you – 比“Thanks”更加正式。我有时用这个。

Thank you! – This doesn’t have the same grating quality as “Thanks!” The added “you” softens it.
Thank you! – 这个不会像“Thanks”那么让人不悦！多余的“you” 使它变得缓和。

Many thanks – I use this a lot, when I genuinely appreciate the effort the recipient has undertaken.
Many thanks – 当我真诚的感谢收件人所付出的努力时，我常常用这个。

Thanks for your consideration. – A tad stilted with a note of servility, this can work in the business context, though it’s almost asking for a rejection. Steer clear of this when writing a note related to seeking employment.
Thanks for your consideration – 有点生硬带点屈从，尽管它几乎是寻求排斥，但是在商业邮件中它很有用。当你写就业相关的邮件时，避免使用它。

Thx – I predict this will gain in popularity as our emails become more like texts. Lett would not approve.