Zas, it really depends on if you are speaking formally to a large group or in a smaller, less formal setting. If you have just given a speech and are thanking the group for their attentiveness, you might want to say: "Thank you all for being here." or simply "Thank you." or even "Thank you for your time." However, if you are speaking to a smaller group and it is in a less formal setting, you could say: "Thanks all!" Honestly it depends on who your audience is/was and what it is you are thanking them for.
I'm sure others will add their thoughts because there are probably 100 ways to go about this one!