I also think it's important that each page of a site be considered as a part of the whole. The example I used in my response to Anil Batra's post was to consider the site as a book and each page as a chapter in that book. You can pick up the book, open it to any random page and start reading but you're not going to "buy" that book unless what you read makes you want to read more. If a single page in a book is enough to cause a purchase, great, but what happens if the book fails to deliver once the reader takes it home? That author's sales aren't going anywhere fast. On the other hand, what if the reader reads a few more pages (aka "browses the site") and likes what they read? Then the book goes home with the reader, the reader remains satisfied and goes back for more books by the same author.
In the web world, that equates to branding. Even if the visitor doesn't "convert" during this visit, the longer they're on your site the more they're branded. They may not buy the book this time but they'll come back and give another book by the author a look, and that one might sell.
I agree that homepages aren't as critical as they once were (Anil Batra's thesis) and I do think they are the cover to the book. If the reader is interested but not yet hooked, having a good book cover can make or break the sale.