Pixel-by-pixel is an abuse indeed, sizes are huge, generation easy. It's like generated ascii art vs hand-made thoughtful pieces of work.

I like to rebound some dribbble shots with css3 http://dribbble.com/ideamonk/projects/97353-Pure-CSS3

I enjoy two aspects of this -

1. Figuring out what the overall is composed of by looking hard

2. Rendering with limited power available in CSS (no photoshop ninja here)

And sometimes I animate them too - http://heldfree.com/play/dropbox/ (best viewed in Safari)

With these I've also found a few subtle differences between how Chrome and Safari render translucent gradients, large shadows, etc.

This is a somewhat rewarding but an entertaining thing to do :)