After my iBook died due to the logic board issue, I had to endure using my backup IBM laptop. Let me tell you, the experience is so much better on my iBook. It's faster, performs more constistantly, has a beautiful sharp vivid display, and is just generally easier to navigate and use.
It's a huge improvement. What's funny is, while I had my Windows machine, I can't say I suffered or anything. But, going back to the iBook was a bigger improvement in my online experience then I expected or remembered. It's great to be back on the Mac!