What is the most commonly used way to say "thank you" in Chinese promotional and marketing materials? I may appear in my company's marketing materials that will cater to a more international base and it was requested that I simply say "thank you" in Mandarin in a way directed at our Chinese client base. I have some experience in the language and I did live in China, but I am not sure what what would be the most appropriate way to say "thank you" to clients. I remember seeing promotional ads for cell phone service and they always seemed to feature much more formal honorifics and courtesy than the spoken language (consistently having "您好" at the beginning of blurbs). Should I lend a more formal tone for this kind of thing or would a consumer base expect a colloquial tone? 

I myself was thinking of saying 非常感谢 for my part just so I could have more than two words to say (it literally may be a video of people just saying thank you in different languages) -- but I was not sure if that would seem awkward or inappropriate in the context of a client facing thank you video. Are there any other commonly said thank you expressions in this context or am I overthinking it when a simple 谢谢 suffice?
谢谢,感谢,非常感谢,深深感谢 all work. Whether you should lend a more formal tone depends on what you're promoting/marketing, and who your target audience is. Trying to sell exclusive membership to a country club to rich retired people, for instance, will be very different from trying to sell computer games to teenagers. Generally speaking, the four-character phrases are more formal, and 谢谢 is the least formal among the four.