[NewGuy]

iPhoto - Daily
iMovie - Weekly
iWeb - Monthly
Aperture - Tried the 30-day thing but most likely won't step up for the paid version
iDVD & Garageband - Seldomly

 

[NewGuy]

I'd use Aperture if I had a Mac run that could run it.

I've done an impromptu poll on both this site and Flickr to test the use of Aperture vs. Lightroom. It seems as though Lightroom is winning by a margin of around 5 - 1.
Not scientific by a long shot but something to keep in mind....