iPad. I know alot of you are apple haters, but the large catalog, fan base, and support blows all the others away. You will 9 times out of 10 always see a release of application for the iPad first followed by the android market.
Do not expect to replace your laptop and people who think they can with the "right" tablet is kidding themselves. IF you require a keyboard or windows based then a small netbook might be the better option.
I use my tablet everyday for 1-2 hours. I have begun to use it in the work field. My sister, a Federal Probate officer, is issued am IPad as their "laptop" and have apps for access to everything, so they can work anywhere.