I would have liked to see head, tail, tr, uniq, and cut. I end up dragging over the old "gnuwin32" versions of those to a lot of Windows machines. Those are my go-to tools for quick-and-dirty log analysis.

I know I could use Powershell for those kinds of tasks, and I certainly do make a lot of use of Powershell, but the familiarity of those simple tools and the decades-old "muscle memory" of using them on various Unix, Linux, and Windows boxes makes them hard to ditch.