RIM Playbook running QNX is a great tablet. It has solid hardware, great build quality and a initiutive GUI, however it's only available in 7" which to me is too small.
The iPad 2 is a great tablet however lacks a tablet centric OS though with 65.000 + tablet centric applications the iOS platform surely lies a step ahead of Android
The release of Samsung Galaxy Tab 10.1" is in June I believe, this tablet focuses on enhancing the android experience. It has solid build quality, solid hardware and a beautiful 10.1" IPS Display. With Honeycomb powering the tablet this is the first real iPad challenger and the only tablet I am thinking of purchasing.
If you want to lower your price points tablets such as the Archos, Acer Iconia and Nook Color will be great. Though Nook Color may be slower then the other two the dev support is simply amazing and allows you to tinker the device to the extent where it becames state of the art in terms of user experience.