6 GB, a brighter screen and 18 hours of battery. Discontinued seven months later to make room for the nano.
Released February 23, 2005 · Discontinued September 7, 2005 · From $199 (4 GB)

The second mini fixed the only real complaint about the first. 6GB for the same $249, a brighter backlit screen, 18 hours of battery instead of 8, and a $199 4GB model underneath it. Gold went, unmourned. Apple killed the whole line seven months later and replaced it with the nano, which was smaller, used flash memory instead of a Microdrive, and had no moving parts to break. Discontinuing your best-selling product to ship something that obsoletes it is the sort of thing Apple did more readily then than now. The mini is still the iPod a lot of people picture when they think of one.
The second mini traded the original's colors for longer battery life, and reviewers focused on the build and the sound.
The metal feels literally cool and sleek in your hand, and it is just heavy enough to be substantial, like a candybar-style wireless phone.
Overall, we felt very pleased with the new mini's sound, and wouldn't hesitate to recommend it on this score.