"2,500 requests may be sent to the Geocoding Web Service per day from a single IP address" - I don't remember this restriction from the previous version of the API. Has this changed, or did I just miss a T&C somewhere?
It all depends how you develop your map, of course, but this is a powerful incentive not to proxy the requests through your own server. And if you need to cache them or whatever, have the user's computer make the geocode request on your behalf, and then send it to the server for storage.
"If more than 15,000 geocode requests in a 24 hour period are received from a single IP address, or geocode requests are submitted from a single IP address at too fast a rate..."