I've been working a lot with geocoding, and I've been looking at Yahoo, mapquest, google, bing and navteq. The free versions are all pretty similar except for the geocode requests. I think you have it right. If you want more requests you need to pay for them.
I would also suggest looking at reliability and accuracy. I like google maps the best, but it's been pretty inaccurate compared to bing which is right on. Navteq seems to be one of the better ones but their API isn't as user friendly it seems like. There are some restrictions for the free map service. Usually, the site needs to be publicly accessible and free, as in you cant charge for service. There are some other ones, but those seem like the ones that catch people up the most.
