Lightroom’s Slideshow is in my view the least impressive of the program’s 5 modules and sorely needs more development effort. To damn it with faint praise, it is OK. In fact, creating standalone slideshows is about the only thing I use Aperture for, sending finished JPEGs over to it and then taking advantage of features such as controlling individual slides’ duration and adding multiple sound files. Of course, that’s only an option if you have a Mac, but if so it’s cheap enough via the app store to make sense as a slideshow authoring tool alongside Lightroom.

It’s worth noting that the term “slideshow” seems to be applied to a few very-different activities:

• Powerpoint style presentations. You’re running a show manually and perhaps have a single track of background music. Lightroom is OK – only – for this type of slideshow but it still lacks polish. For instance, when you set a slideshow to run automatically you have smooth transitions between slides, but not when you’re running a show manually.
• Standalone movies.  Here you’re creating something that might run over the web another definition of “slideshow” and Lightroom can generate. But it can’t produce an Animoto or Soundslides-style audiovisual slideshow, mainly because of the inability to time individual slides (I’m pretty sure I asked them!) and match pictures to more than one sound file (I’m certain lots of people have asked them). Aperture 3 can do both, so you might just export the JPEGs from Lightroom and use Aperture for the slideshow.
• Proshow-style shows. This kind of slideshow is a slightly different beast and is great for authoring wedding DVDs where you want .

more for standalone slideshows with front menus, music – you know the kind of thing,