What are people doing that you are thanking them for in every email?
Personally I find a bare "thanks" when there's nothing you should be thanking me for a little off-putting. Of course not everyone shares my view.
If you must add the fluff, Regards, Cheers, or something similar would be better in my opinion. I tend to leave greetings and closings off unless the email is very formal, and "thanks" is too casual in that context.
It really does depend on the context though. If I'm asking someone to do something, I might close with "Thanks in advance". If they've already done something for me, I thank them in the body of my email.
I came across an article that had an e-mail in it that summarized nicely why I find "Thanks" or "Thank you" as an e-mail closing when there's no reason to be thanking me off-putting: Adblock Plus blocked from attending online ad industry’s big annual conference
It turns out that while some folks use it as a closing regardless of the tone of the e-mail they're writing, my experience is that "Thank you" or "Thanks" tends to be the go-to closing for folks who are writing e-mails to brush people off or terminate a conversation. I tend to read it as "Thanks - you can show yourself out" and I end up looking back over the e-mail for clues to decide if that's just the standard closing that person uses or if they're really being that dismissive.