After a useful call from Ben Goldacre, here are the wireframing tools that look useful for the sort of thing that I want to do: early conceptual website design. Question: is it better to get something that looks more or less like a website (e.g. paper sketch vs quite close-to-life / interactive)?

• Balsamiq (nicest demo by far, $79 for desktop version)
• Creately (not sure on pricing, basically Visio online, but reasonably responsive)
• iPlotz ($75 for desktop)
• Pencil project (Free Firefox addin that won´t install on 3.5b4 at present)
• Powerpoint template (free and serviceable, but doesn´t look quite as easy to use as Balsamiq)
• FlairBuilder ($99, more PowerPoint in nature)

While I don´t think I want it now, Jumpchart looks useful if you are going to end up with a WordPress hosted site as it will create a file you can import directly (for $25/month, but you can upgrade and downgrade each month).