I hadn't realized before fooling around on ebook comparison site Leatherbound.me that the Nook and iBook stores had such a rubbish selection of books. It wasn't until I typed in "Twilight" that I actually found something available on all stores.
Truthfully, I wasn't that interested in the iPad as an eBook reader. Then I used it, and I must say, it's a mostly wonderful experience that's only crippled by a disappointing store.
Bad luck, non-US countries. iBooks won't be available from launch in any country other than the US. That could mean Apple's still to finesse the licensing details with book publishers in each country, or you're just plain out of luck.