A great new tool in Photoshop CS3 (or rather, an improvement over an old tool) is the "Smart Sharpen" filter. I've already started using it in place of the tried and true "Unsharp Mask" filter. By the way, who at Adobe names these filters anyway? Wouldn't a rational person conclude that a filter named "unsharp" would make their image less sharp, not more sharp?
Regarless, the Smart Sharpen filter is great because it enables different types of sharpening, a much larger preview and the ability to limit sharpening in the highlights and shadows. This last feature can help eliminate those nasty color halos you get when overall sharpening is applied to an image. You can also save your custom sharpening settings for later use. Very sharp, indeed.