[proexploit]

I think it's inaccurate to say most designer's work process is to "just sit down and muck around with fonts, shapes, etc until they have something that fits the bill". Of course design is a process but all those "lovely theoretical things" tell you where to start. If you're quoting by rolling the dice, you're not quoting effectively.

[prawn]

I don't want to truly trivialise it, but I imagine a lot of it is brainstorming, thinking, and gut feel than direct conversations with customers, market research, etc.

And I have to disagree on the dice. The best situation is a client giving me their budget and me telling them the best way to spend it (often, not all of it). So, when the budget is not disclosed, instead of spending hours trying to guess their pricepoint, I just randomise the approach and then fill that budgeted time in the best way possible.