I would find an external iPhone/iPod Touch keyboard useful if it was one of those folding ones, and it actually worked with the app in which I do a lot of typing (Proloquo2go). As it stands, that particular keyboard is pretty silly.
I don't get what's stupid or useless about a wrist strap for MP3 players. I think I'd like that better than a bicep strap. I don't want my MP3 player next to my sweaty armpits when I'm exercising, and it's much easier to look at the screen when it's on my wrist than if it was strapped to my upper arm.
