First you have to know what you want to DO with it. If you want to be able to work with desktop applications like Word, Power Point, Excel, etc., then Palm is right out. However, if you just want to keep track of your contacts, schedule, and calendar, then you might want to get a Palm. Which Palm depends on what you want to do also. If you want to cruise the net realtime, you will need to get a Palm that works with wireless. Not all of them do. Used to be that Pocket PC's were more expensive than Palm devices, but now you can't say that. Palm devices used to have really long battery life. Pocket PC's don't. Well, now, a lot of Palm devices are using Lithium Ion batteries, because they have color screens, wireless communication, some are even telephones. All of this adds up to shorter and shorter battery life.
Pocket PC or Palm, the number of applications you can load depends on the size of the memory. Palm devices have historically been short on memory. My HP Jornada 568 has 64 Mb of RAM and I have another 256Mb memory card in the expansion slot all the time. I can play MP3's at the Y and have lots of programs stored on the 256Mb CF Card.
So, to sum it up, you need to decide what you want to do with it. Then, you can find the machine you want.