Some of Lightroom's advantages are its compatibility with both Mac OS X and Windows, its nondestructive editing capabilities, its fast performance, its integration with Adobe Photoshop CS5, and its support for editing presets.
The video for photographers features photographer Julieanne Kost and outlines some of the great new features of CS5, including the new HDR merge and the improved demosaic and sharpening tools.
Adobe's Official Demo: This demo is produced by Adobe and highlights some of the new features of Photoshop CS5.
This demo is more of a brief overview of what is new in CS5 and designed to generate interest in the product.
This site is full of videos which explain Photoshop CS5 in context for different users.
Adobe TV: This is another site designed by Adobe as a demo for their CS5 launch.