5Hz sampling is a waste of time and money on a consumer GPS. You haven't moved far enough in .2 sec to make any difference. Any bluetooth GPS will work fine, AFAIK they all use NMEA protocol and standard bluetooth connections. I have an F-tech with solar cell, which gives somewhat longer run times during daylight. I don't think that's very important, however. It cost about $35 and works fine with everything I've tried it on, including Palm, Windows, and Linux.

The GPS receiver doesn't give you voice directions, mapping, or anything else. Software does that. Standalone units, such as the Garmin Nuvi, have both the hardware and software in one unit, and you don't need anything else with them. They even have mp3 players and bluetooth for phone connections in most models, so you can call the restaurant you're being guided to. You pay for that capability, of course.