Chong Khneas
This is the village most people visit and the one most often touted by tour guides, guesthouses, etc "you go see floating village?" and a quick boat trip around the village will not only show you people in conical hats, which usually makes them Vietnamese, going about their daily lives, but you'll also bump into a dozen other small boats ferrying camera-toting tourists going about their daily tourist lives. To be perfectly blunt about it, we think this village is a cruddy tourist trap and not surprisingly, many of the locals are either thoroughly tired of all the tourists floating around their neighborhood or have devised ingenious ways of separating them from their money. Still, if due to time constraints it's the only lake village you can visit, then we guess it's better than nothing. But if you do go to Chong Khneas, the Gecko Environment Centre is well worth checking out as you can learn quite a bit about the ecology of the great lake.
The tourist police took over the Chong Khneas tourist boat operation in November 2003 and take the lion's share of the money. The prices were supposed to be fixed, but in fact the police will try to get from you as much as they can and your driver will be expected to help. Drivers and tour guides are given a kickback and strictly prevented from bargaining on your behalf. The person who actually takes you on the trip, the boat operator, sees very little of this money and as a result will often be more interested in getting you to buy stuff than actually show you anything interesting. Yes, this whole system stinks.
At its worst, the boat driver will mysteriously and conveniently breakdown in the middle of nowhere and ten boats will surround you trying to sell you junk. Meanwhile the boat driver continues to try "fixing" his boat, a successful repair occurring right about the time you give in and buy something. At its best, the driver simply stops at every possible place where someone could sell you something, usually a restaurant.
Or avoid all the unpleasantness and simply avoid Chong Khneas.