I've had an iPad for over a month now. In short if you want a tablet that will work with the Internet seamlessly and allow you to manage your media files then you are out of luck with the iPad. The iPad is designed to do things that Apple wants to allow you to do with the hardware. If you play games they best not be flash or java based and they had better come from the Apps Store or you are out of luck.
If you have a good collection of AVI, DivX and other video formats you are going to need to buy a converter because iPad does not play what Apple doesn't want you to play unless you convert it to a format that it will deal with no matter how bloated M4V is over AVI.
Apple is part of the growing tide of hardware producers who want to control what you are allowed to do with the hardware they sell you. Imagine if you bought a car and were told that you could only buy gasoline at those stations preapproved by the car manufacturer and if you put gasoline in your car from someone else then the warranty would be void and during the next upgrade the car would become nonfunctional.The iPad is a nice piece of kit. Looks good. Holds a charge well but if you actually want a functional piece of equipment it falls a little short. The keyboard is a joke. The once brilliant lock screen button no longer functions as such and has been changed to a mute button (no one knows why). Want to watch Comedy Central - no dice. NBC considered streaming content to iPad for a fee but still streams for free to Windows using Flash. In short the functionality that you really want to be there if you are expecting to use this as a kind of multimedia device just is not there. This is one of the few times it looks like waiting for the Windows version might be the wisest decision you make. If on the other hand you trust Steve Jobs to understand what you should and should not be doing with the hardware you buy then go ahead and get one.