True, it is also good to have an idea which tone means what. As far as I know it's: high-level, raising, falling-and-then-raising and falling (the shape of the dashes over i gives the hint) http://en.wikipedia.org/wiki/Mandarin_phonology#Tones

That is awesome! Illustrative diacritics, who would have thought? I still would love to hear the sentence spoken.

http://www.mdbg.net/chindict/rsc/audio/voice_pinyin_cl/shi1.... (shī)

http://www.mdbg.net/chindict/rsc/audio/voice_pinyin_cl/shi2.... (shí)

http://www.mdbg.net/chindict/rsc/audio/voice_pinyin_cl/shi3.... (shǐ)

http://www.mdbg.net/chindict/rsc/audio/voice_pinyin_cl/shi4.... (shì)

For the falling-then-raising (shǐ) changing the "shi3" to "chi3" in the URL gives a better idea, I think, for what the inflection sounds like.

Agree on the last point -- at least, for Taiwan. In fact, those idealized graphs caused me a bit of a headache early on. Native mandarin speakers in Taiwan tend to drop the end of the 3rd tone, so it falls slowly then holds at the bottom for a minute, then rises slightly or even just cuts off.