So looking through the What's new in Aperture 3 page, it looks like some people's dreams will come true, with "Faces" and "Places" from iPhoto appearing, brushes for retouching (echoing the local adjustment brushes from Lightroom), presets (they didn't have those before?), and what looks like a gorgeous full scren browser for browsing and viewing. Rounding out the major features is new slideshows with advanced affects, ability to combine video and audio with your photos, etc (sounds like they mixed in some Final Cut/iMovie in there as well).
All I can say is I kinda wish I a) wasn't already invested in Lightroom (come on Adobe, bring us Lightroom 3!!!) and that my main and most powerful computer wasn't a windows machine.