Palm V (or rather Palm Vx and Palm m500, which are essentially the same in spirit) is my idea of a perfect PDA. Sleek, lightweight, with a battery charge which runs for weeks. A spartan monochrome LCD with a soft green backlight. Easy on the eyes. A low power consumption (Motorola DrangonBall) CPU. Enough memory to keep a medium version of WordNet and a small library of select e-texts. Perfect to make sure your favourite book is always at hand, to store all the passwords, addresses, and schedules.
As a downside, it can be noted that Palm V is produced by an evil corporation and runs a lame proprietary closed source OS. From the practical angle, there are certain light conditions when it's nearly impossible to read the screen either with the backlight on or without.
Unfortnately, most later Palm models have either a plastic body, a colour screen, a fast processor, or all of the above, and, as a result, are too low-end, or too heavy, or too thick, or have a battery life too short.