There is a lot of conventional wisdom, especially among programmers, about the benefits of having more monitor space in order to be more productive. Rather than throw out a pile of links, I'll put just one here, a link to an article that has lots of links in it.
Sometimes, however, we just don't have the luxury. I have multiple monitors at home, but only one at work (a 19" wide), and neither the spare cash to buy myself a second one nor permission from On High (tm) to acquire one with company money. So that's the way it is.
What I'm wondering, from folks who only use one monitor (whether by choice or by necessity), is what techniques, tools, and practices you use to keep limited screen real estate from being a thorn in your side. I've been using VirtuaWin for a little while now, and it helps, up to a point. I use Alt-Tab so liberally that I'm a little worried about breaking the keys. But there have to be other techniques and software out there for alleviating the downsides of not having much space to work with.