Started with the 16gb wifi
I started with the 16gb wifi thinking that I won't need more. Then after a week with the ipad I was sold on what it could potentially do, especially sitting at a coffee shop without wifi, but with the ability to get email, browse the net via 3g.
So I went for the 3g model and since I was doing that.... why not more memory (after all after you commit on your purchase there is no upgrading).