Smashing Magazine gives a great list on Mac Apps that help boost productivity. I of course love Adobe's CS4 Kuler extension panel. It connects directly to Kuler, the web-hosted application for generating color themes. Logging into Kuler.com with your Adobe ID, you can create color swatches themes from a color, share, rate and search the community color schemes, and upload or use a Flickr image to extract color themes so you can download them as an Adobe Swatch Exchange file that’s compatible with Adobe applications.
Paparazzi! is another favorite of mine.
It's a small utility for Mac OS X that makes screenshots of web-pages.
Thanks DesignNewz via twitter