] Another JA irony? That sentence applies to Bingley rather than Darcy.

I'm not sure what you mean by this. :-) Do you mean that it's ironic that the ladies should all be setting their caps at Bingley when a man like Darcy, even more handsome, twice as rich and who actually owns a grand estate should be following him into the neighborhood? If so, I hadn't quite thought of it like that myself, at least not in relation to that famous first sentence.

But JA does give us an interesting situation when the two of them walk into the Meryton Assembly together. Darcy creates a sensation just by his presence and his bachelor credentials make their way around the room quickly enough, don't they? ;-) It gives us sort of an accelerated view of how the news of Bingley's taking Netherfield spread over the neighborhood, I think.

In fact, I think that first sentence sets the tone for the book's humor and playful irony. The scenes that follow, with the back-and-forth between Mr. and Mrs. Bennet, give a good indication of what we can expect with regard to characters. Finally, the Meryton Assembly brings the title into focus and sets the stage for what I think is the main point of the book--how Darcy's (and other people's) abominable pride and Lizzy's (and other people's) prejudice can create a gulf of misunderstanding.