Check out the reviews on current PDA's:
http://www.zdnet.com/products/stories/reviews/0,4161,2684563,00.html

Prism and Platinum received excellent marks. For the Prism, the 160x160 resolution is the main complaint.

Myself, I consider the springboard platform as the best interface for peripherals.
I'm waiting for color to come down in price before I give up monochrome.
However, if I really wanted color TODAY, then my choice would be the Compaq IPAQ because of the color resolution.
I've seen the Palm and Prism color displays. Resolution is not good enough for the cost of the units.