Hmmm... I actually really enjoyed The Fountainhead and it remains one of my favorite books till today (roughly 7 years later). I have not read Atlas Shrugged because several people told me it would ruin The Fountainhead for me (including my mother who has almost identical taste in literature as I do.)
I have read some of Rand's essays and listened to some of her lectures on tape and I think the woman was absolutely off her rocker, but I think that there are messages in the book everyone can walk away with, provided you don't take everything literally. I thought that the drama of the black and white nature of the book, and the self-destructive nature of the characters (something we all possess) is what really kept me reading.
As for the characters, I like to view them as allegorical in their representation of various character traits whether cowardice, greed, passion, determination, beauty, etc. As someone else mentioned, Rand's characters are entirely black and white - and so represent the absolute extremes of human nature, which I think can be a useful tool in proving points (as has been done historically in most religious tales). I, however, DO NOT, as most of Rand's devotees seem to, think her writing should be taken as religious gospel (for that matter I don't even treat religious texts as requiring literal interpretation).
I think that The Fountainhead brings to light important virtues and vices, but in extremes, and though it was a little ridiculous that all ended well for the protagonists, I don't think that really took away from what the characters were demonstrating. This is what I got out from it:
Elsworth - appeared to be benevolent but was actually a very spiteful, unhappy, scheming person who wanted only to be in control and had no actual regard for others. Remained miserable.
Keating - Spineless, all show (in his architecture and personality) with little substance, couldn't get what he wanted, resorted to murder and still couldn't.
Rourke - Stood up for what he wanted, never went out of his way to help others but also never did anything to harm anyone else, followed his heart, came out the winner
Dominique - one screwed up, self-destructive bitch, but she actually did understand Rourke and in the end somehow everything worked out
Her husband/newspaper tycoon/I can't remember his name anymore - similar to Rourke, a self-made man, but he allowed power to get to his head and was unhappy, ultimately though he relented.
To the OP, sorry I didn't respond to your question... I was just disheartened that so many people seemed to hate The Fountainhead.