I'm not totally sure whether this is the right spot to ask this question, but here it comes.
When creating scientific posters, you often have to place text, figures, and formulas on a large (A0) paper. There are programs that are commonly used (e.g. PowerPoint), which neither make good text layout nor support formulas. Other programs are great with text and pictures but don't make it easy to have complex formulas - especially formulas inline with the text. And while you can create the complete poster in Latex, which this question is about, I'd really like to use the mouse to do the layout.
So, what solutions have you come across that more or less do the job of creating a scientific poster which includes Latex-formulas?
I'm mainly interested in free software, but please also give commercial solutions as answer. Also the operating system doesn't matter that much. I'm using Ubuntu but can go to Windows, too. If it's Mac, well maybe it helps someone else.