If your entertainment in Vegas is solely reliant on what street-level shows you'll get to see for free, the Bellagio fountains are universally considered the best.
Seeing a few hundred people practically camping by the railing to watch the fountain show felt similar to Disneyland Resort goers setting out blankets and waiting hours on end for Fantasmic or World of Color to start. It gets really crowded.
The Bellagio's fountains attraction has cachet with their seemingly simple shows of light and water set to music. It's certainly better than waiting for the "volcano" at The Mirage to erupt, the destruction of Pompeii in the Forum Shops attached to Caesar's Palace, or to see the recorded porn-level acting with random dancing in Treasure Island's pirate show. You could argue the Venetian's Streetmosphere has the class, but it's not to the scale of the fountains.
It's enjoyable no matter what language you speak or how much you've got in your wallet.