I did this. Existing floors were extremely poor condition, not possible to refinish. But, some small spots were ok, and overall the floors were flat.
I covered everything with the thin foam sheet the laminate manufacturers require, then put down the new floor. I bought fairly good quality laminate, not the home depot shit, look at the seam design and fit to get a feel for the quality. It was fairly easy, cutting to fit around radiators, etc. was a bitch, the dense fiberboard seriously dulls saw blades.
It fits together quite tightly and water does not seem to penetrate. The exposed plank under-overlap seams supposedly are wax coated. Read their test and warranty literature, it's fairly impressive. I haven't had any problems in the front hall with wet shoes or with kitchen spiils. Also, several beer bottles, wine glass and coffee cup spills over the years with no damage or smells.
In terms of looks, I'm pleased with it. Numerous visitors have complemented me on it too. But I waver: overall the large expanse is quite uniform looking. Sometimes I think, damn that looks nice, other times I think the opposite, too uniform.
Overall, for about 600 square feet, it cost between 30 - 50% of new hardwood installed including the tear out of old floor. Also, I did it all in about one weekend, minimal mess.