Presentations, the slide show component of Google Docs, has been updated to allow slides to be given custom background images and colourised. While there's still no ability to save create constant self-made themes, it does bring Presentations one step closer to being a feasible alternative to desktop-based slide show creators. The update also makes it easier to select and move more than one slide at a time by Ctrl- or Shift-clicking and dragging slides around. Having been out for two months now, are you finding Presentations useful? Share your observations in the comments.