Emailing is a cold communication, all business, and yet I regularly get messages signed “warmly”. Automatic signatures have the opposite effect on me; rather than establish a connection, they form a barrier because they are block and copied, and therefore a pat response. I have always signed my emails “sincerely” or “thanks very much” and have since read, in a Forbes blog by Susan Adams, that this is archaic. Here are a few of Ms. Adams’ other insights:

Best Wishes –Seems too much like a greeting card but it’s not bad.
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.
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.
Thx – I predict this will gain in popularity as our emails become more like texts. 
[:-) – I’m a sucker for variations on the smiley face made with punctuation marks, though I suspect most people don’t like them.
In haste – Good when you don’t have time to proofread.
Be well – Some people find this grating. Not appropriate for a business email.
Yours Truly – I don’t like this. It makes me feel like I’m ten years old and getting a note from a pen pal in Sweden.
Ciao – Pretentious for an English-speaker, though I can see using it in a personal, playful email.
XOXO – I’ve heard of this being used in business emails but I don’t think it’s a good idea.Have a wonderful bountiful lustful day – Tim Ferguson, editor of Forbes Asia, regularly gets this sign-off from Joan Koh, a travel writer in southeast Asia. It’s weird and off-putting.
Sent from a prehistoric stone tablet – I laughed the first time I read it but then the joke wore thin.
This email is off the record unless otherwise indicated – I’m wondering what kind of paranoid people put this in their signatures.

Thanks, and I mean that sincerely, McPhedran