Creative Software

I am new to Mac and would like to learn some creative software, in order to create newsletters and other collateral. I am not looking to become an expert, but want to be able to come up with something nice. I'm also not looking to only rely on templates. Let me know what you think I would be able to learn, considering I'm new to Mac and creative design. Thanks!

For newsletters and simplicity and power, consider Pages (part of iWork). Excellent program. And you get an even better Keynote for presentation.