Having some experience with the side effects of prolific tagging on Programmers, I would suggest we start using meaningful tags now and avoid the use of over-tagging: it's a heck of thing to try and clean up after the fact.
If people see that most questions have 3-5 tags, they're going to start adding tags without thinking about what those tags mean or how they're used elsewhere just to make sure their question "looks" like all the others.
I think in these early stages, we're likely going to be able to pull off having 1-3 tags instead of 3-5: many tags mean the same thing, more or less, when it comes to organization, and the really specific tags being added now will likely wind up only having one or two questions in them, making them next to useless. So when in doubt, it's probably better to opt for the more general tag than creating a new tag for whatever the question's talking about.
To that end, I think it's probably good if we nail down a set of 20 "core" tags, get tag wikis in them, and then start to branch out from there.