That's not entirely true. Gateway has a new wide screen, ultra-brite, convertible that can be had for around $1000.
Here's what I see the pros and cons being
Convertible - Pretty much behaves the same as a laptop does, has usual complement of USB and/or PCMCIA slots. Since they are more like laptops, they're heavier then the other tablets. Of course, my recommendation in the convertible form factor is a Gateway convertible. It's been getting great reviews since they've come out, has a great price, and an awesome battery life.
Slates - These are usually smaller and lighter then the other tablets. A slate does not have a native keyboard. That doesn't mean one can't be used though. Most slates have some USB ports and/or ways to get bluetooth on the slate so that a bluetooth keyboard could be used. The problem I see with this situation is where do you prop up your slate while typing? I'm not as familiar with the slates but I believe Motion computing has the best slates on the market.
Hybrid - As far as I know the HP TC1x00 is the only hybrid out there. And HP just recently stopped making them :disgust: This is what I have and can speak at length about. The TC has a detatchable keyboard so that it can be used in slate or keyboard mode. Not only does the keyboard detach, but it will also fold flat with the screen like the convertibles. It has good battery life (about 4 hours with WiFi off). It's really light, about 3 lbs without the keyboard, 3.5 with. It has a great docking station that can be used with it that will provide 2nd monitor support, CD/DVD drive, and extra USB ports. The things you may not like about the TC is that it has no embedded drive, CD/DVD/Floppy (but it has 2 USB ports to connect and external one). The screen is a little small at 10.6 inches. Once you get used to it it isn't too bad. It only has one PCMCIA slot, but it does have a dedicated compact flash port. The slower version, the TC1000, is kind of underpowered and can be slow at times with its Transmeta chip. The TC1100 does much better with a Centrino Mobile processor.