Remember that just like computers, PDAs will ALWAYS be getting better, smaller, and cheaper. If you wait for the "best" one, you'll wait forever.
If you find a couple that suit your needs now, compare, find the best price, and get it! Remember that just like you don't keep the same car or computer forever, you won't have the PDA you buy today forever.
Craig uses the HP series of PDAs, so he can give you specifics on these machines. I also believe that Jeff is quite knowledgable on Zeos machines. So they can give you particulars.
In general, you need to ask yourself a couple of questions to determine which PDA is best for you. For example, is pen input a must for you? If so, then the Newton and Zoomer are going to be high on your list. If you can afford one and think that more than a PDA is what you need, you may wish to look at the AT&T EO as well. If pen input is not important or even desireable, then you have a lot more choices. The HP and Zeos machines, of course, but you may also want to look at the Psion machines. These are EXCELLENT PDAs, especially if you think having voice input may be important to you. Also, please don't ignore the Sharp Wizards as they are superb machines as well.
Finally, post lots of messages here and ask lots of questions. We've got some of the top people in the industry lurking around here and they'll be glad to help you out.
Joe