I really doubt the price will go down, but the features will definitely go up with future upgrades. Basically you will be paying the same price for a slightly better product (better OS, camera, more memory...).
Though eventually Apple will release a radically upgraded version, and keep the old version but make it cheaper (just like the iPhone 3GS vs the 3G), in which case you can purchase the cheaper/older model. Apple always follows the same pattern.
I say if you don't really need it, don't buy it and wait for it to get better. Personally, I will buy it only if Apple (or someone else, for that matter) ports Mac OSX to it. For right now, it is too much like an oversized iPod Touch for me.
If you really want a tablet, you would be better off waiting a little while (within the year) for the HP Slate, which will have all the nice features that the iPad doesn't, including Windows 7, and probably a slightly higher price. Between these two companies, though, you can't go wrong.
