I held off upgrading last year because the improvement between v1 and 3G was not worth $299 + tax + increase in monthly fees to me. But I upgraded from v1 to 3GS (32GB) because the improvements were much more and with potential for it to be even greater (MMS, tethering, faster 3G).
So using my logic maybe going from 3G to 3GS is not worh the $350+. But your case is different, you were forced to downgrade to v1. So it depends were you see yourfelf at this moment, a v1 user or a 3G user
It's really a personal thing. Over a 3G the only "feature" I consider meaningful is the camera upgrade. Is that really worth the cost? The speed is a minor upgrade, as is the compass. The higher speed internet capability is unusable in the US at this time, and since you're not even using a data plan pretty meaningless to you anyway.