So I gave into weakness when I was in Chicago a couple weeks ago, because goodness knows when they're actually going to launch them in Canada now. A couple apps that haven't been mentioned in this thread:
* Instapaper: You can sync web articles (or email text) to this service, and they will sync to the Instapaper app so you can read them later. Great for queuing up articles to read over lunch, or on public transit, etc. The Instapaper site itself can also export to Kindle or ePub format, or give you “printable” versions. And, if you share an Instapaper account with some trusted friends/co-workers/other colleagues, it's a great way to share stuff you're reading with each other.
* Air Video: This is a great app for streaming video in a variety of formats from another computer. That computer needs a little server app installed, and you simply tell it what directories to stream to your iPad. If it's in an iPad native format, it will play as-is. If it's not, the Air Video Server app on your computer (Windows or OS X) will convert it on the fly and stream it over. This is awesome for those of us that rip all our TV shows and movies onto a media server — the iPad is truly on-demand video anywhere in my house, with no need to sync stuff via iTunes or encode video into an iTunes-friendly format. (It can stream over the internet, too, but I've yet to test this.)
* Blokus: This board game is just plain awesome. I had been holding off on buying the analog version of the game, but the $5 spent on the digital version has made the real version an essential purchase before my next board-gaming night.
* Marvel Comics: This app makes reading comics just gorgeous and is so intuitive and well-thought out. I look forward to DC Comics coming out with a similar app!