A fairly decent poster in Inkscape

Input: nicely polished LaTeX/Beamer slides from the last conference presentation. No concept at all yet. The poster is due in 5 days.
I used to do posters with LaTeX/geometry, but that only works if you have lots of text and a plan. Trying this approach with throwing lots of figures on your empty canvas and shuffling them around is a nightmare.

Inkscape is great for positioning and shuffling graphics, but pretty much useless regarding text editing. Enter the textext plugin. I put additional package definitions (font, paper size to sort out margins etc., amsmath) into a preamble file and set the scaling factor to 2.5 for a 4 by 3 ft poster
The output is a SVG group which you can then move and tweak to your heart's content. To re-edit, first select the group and then the open the textext interface.
The downside of this method are rather long compiling/conversion times - up to 10 seconds in my case. Here's a preamble example (poster font Vera Sans):

\usepackage{arev}
\usepackage{amsmath}
\usepackage{xcolor}
\usepackage[utf8]{inputenc}
\usepackage[papersize={20in,30in}, left=0in, right=0in, top=0in, bottom=0in]{geometry}

a tex code example:

\begin{minipage}{4in}
\textcolor{white}{
\begin{itemize}
\item this equation has Greek indices
\[R_{\mu\nu} - \frac12g_{\mu\nu}\,R + g_{\mu\nu}\Lambda = frac{8\pi G}{c^4} T_{\mu \nu}\]
\item \ldots and those triangles are upside down
\[\rho\left(\frac{\partial \mathbf{v}}{\partial t} + \mathbf{v}\cdot\nabla\mathbf{v}\right) = -\nabla p +\nabla\cdot\mathbb{T} + \mathbf{f}\]
 \end{itemize}
}
\end{minpage}

superimposed over the most discordant SVG background I could find:

Note: That's not quite my poster