Let's start with Boyd's IP Theft (oops, I mean Dictum) on Prototyping Tools: it is easier for someone who knows what they are doing to transfer a design concept on the back of a business card with a crayon than it is for someone without a clue to perform the same task with any other medium.

In other words, the important part is transferring the design concept not look at the size of my tool.

Sure, some tools make things easier. Some tools are more efficient than others.

You've got a heap of choices. Rightly or not, most client sites in Canberra are Microsoft shops, so for portability purposes there is an argument to use XP-friendly prototyping tools. I'm not saying it's right, just easier.

Some I've looked at include:

• Axure: I use Axure because the engagement I was on was in a Microsoft shop and it was the best available at the time. I've grown used to it's good and bad points. Familiarity has bred content. It produces rapid HTML prototypes but unusable HTML - that said, I like the Microsoft Word specification output, because Word is the easiest way to get documents around the current client site.
• Visio: if there is a Hell for IAs, Visio is the tool that they used to design it. The best thing that can be said about it is that it works - one screen at a time. You can do a bit of work with masters and reuse them, but it is all manual and harder work than it could be using one of the add-on sets - like Intuitect.
• Intuitect: Intuitect is a great idea, but has some flaws because it sits over the top of Visio (but I understand that they're working on it, and I look forward to seeing it grow). It is extensible, and can use real CSS (which in turn can be substituted for other real CSS, so "reskinning" should be easy).

There's a lot more to prototyping tools than this - a lot more. This article is a starting place for yet another discussion on the subject.