When making comps for website designs, I usually use Fireworks. There are many advantages to this, such as setting up each page of site on a separate frame, and having constant elements (like navigation) on a shared layer. Underlining text is a cinch too. The only downside I’ve found is that it can run quite slow, especially when editing text. Sometimes, it’s slow to the point of wanting to throw myself on a fork.
So what do you use? I know that Illustrator and Photoshop are the popular choices. Is there an ideal, but unheard of, app out there that I’m missing out on? Or an everyday "who would’ve thought it could be used for that’ type app? Only one condition - must work on OS X.