I've heard good things about AnywhereMap from ControlVision (www.controlvision.com and <a href="http://www.anywheremap.com)" target="_blank">www.anywheremap.com)</a>
It is expensive, but about the same as a Garmin 295. It also seems to have more functionality.
I particularly like the look of the Sentinel GPS card that is used since it doesn't have to have trailing wires (although maybe it does to actually pick up a satellite...)
The initial worries I had about these things were:
1. Trailing wires around the cockpit
2. Brightness of the display
3. Head inside the cockpit rather than looking outside.
4. Fiddly display
I think the new GPS card may address the first one, although an external power source would be required for long flights.
Since getting hold of a Compaq iPAQ, I am less worried about number 2.
The third question is really an issue with any GPS I would think.
The last one I'll only know if I get to use it <img src="smile.gif" border="0">
If you pick one, please let me know how you find it!