Just thowing this out there, what is it you want a macbook for that you are comparing it to a iPad.
For my, I've got a 3 year old macbook pro I bought for bringing to school, doing location recording and editing, and playing games/surfing. Since I bought it my uses for it have dwindle. In the last month, I've only used it to surf the web, watch a movie, check email, and play WoW during my lunch break. I don't do any of my audio work from my laptop (instead on my iMac) So for me, having a laptop doesn't feel so necessary.
My biggest concern was for lack of flash, and I did what P-Worm suggested with click2flash. I noticed that the only things I were missing were ads and the occasional embedded video on engadget/joystiq.
So I decided I'm going to get rid of my old MBP and get an iPad, because it fulfills nearly all the tasks I currently use my laptop for, but in a more convenient package.