You have to make a decision. I lived in London and spent 3 hours a day on bus, tube, or train. If I didn't have my iPod and a book I'd have gone postal in about a week.
Ask yourself if you'll get any added value out of pictures (and remember, anything other than music kills the battery in minutes). Otherwise forget the pretty display. I just loaded up my playlist(s), hit random play, and stuffed it in my computer bag. Never looked at it again.
I'm pretty sure you can get (better) replacement batteries online for about 50 bucks. Why not gamble the fifty and try to replace it yourself? If you do it wrong, you've justified buying a new one! If you do it right, you've saved 400 bucks!
Sounds like a win-win.
A Fixed One or a New One? Buying Your Second iPod