Definitely get him an ipod. I'm not sure whether 20 or 40 (because I don't really know much about that). Personally, I think any gift is better (whether to give or to receive) when its engraved, it just makes it more personalized. Like more thought went into it, not that you wouldn't really think about it, but you know what I mean. The suggestions you have for engraving are good, definitely nothing lovey. If you can trick him by putting it in a different box, that would be really fun, he'd be soooo surprised. Maybe you can get a really big box, and fill it with a lot of fun tissue paper and confetti and then have the ipod inside.
Keep us posted on how it turns out
