I really like Adobe Illustrator. When I was in college we had a teacher (Herman Luft, I believe) who gave us the Macs’ Milk logo and asked us to trace it in Illustrator. Sounds simple enough, but he said you must use as few anchor points as possible! Ever since that assignment I have always tried to perfect that pen tool.
Here are some Adobe Illustrator illustrations:
Zippy Bits Cereal