Looking at the first post, T4 is looking for something handheld/portable with a map view that he can display and manage user waypoints on through some software program.
I think all handheld GPS units can do this. Some of the better aviation ones, like the Garmin 296 series, can also give you EGPWS, full aviation data including airspace boundaries, detailed base maps, voice driving directions from your hotel to your airport - hell, even tell you what gas stations are on the way. Waypoints are managed through a slick interface with your computer.
There are some PDA's that also do the same, the Garmin 3600A for example. I find they are no better in size, not as good for display or controls, and the software generally more awkward than the non-PDA units.
I don't work for or advertise for any manufacturer either, but in my part of the world you'll find almost all the ones used here start with the letter G.
malabo