A good notebook or PDA might come close but is never quite perfect. Still, you don't hear users get anywhere near as passionate about desktop PCs.
Notebooks are the sports cars of computing.
They are an intimate and personal extension of your brain that you can pick up in your hand and take with you. Except they have much better memories and can process infinitely more information than your brain. A professional with his or her notebook is a like a kid with a dog. Put 7 pounds of power into a 3-pound case. And it's happening.