A few people are mentioning how the Bold's screen is small compared to the iPhone. But realize something: it's the exact same resolution, and none of that is ever covered up by a huge virtual keyboard. So doing things like posting in a messageboard will be a lot better of an experience on the Bold than on the iPhone, even a 3G iPhone. As well, the screen will look a lot nicer, *because* it's smaller -smaller pixels without resolution loss always looks better (though it might be harder to see fine detail).
Oh BTW, for people who don't know what it looks like, this is the bold:
http://cache.gizmodo.com/assets/images/gallery/4/2008/05/medium_2484842449_3ca131d2a2_o.jpg