New instruments, what would you do?

[labatt]

It all depends on where you are planning to go. Different plotters use different cartography, and different cartography manufacturers have different strengths in different regions. cMap and Garmin will be the best for the Bahamas since they integrate the Explorer charts. Navionics may be better for Euro and other regions. Just check out the maps first and then pick the unit that uses the maps you like the most. With regards to the rest of the instrumentation, I would focus on NMEA 2000 compatible devices. You'll be able to use different manufacturers sensors and instruments and integrate them as a single system. In addition, you don't have to homerun your sensors and instruments back to a single place. The only place that it COULD be a little difficult is if you need to put a backbone cable to the top of your mast, but you could look at using a Tacktick wireless unit with their NMEA converter box... there are some more details on Panbo: The Marine Electronics Weblog - a great electronics blog.

[hellosailor]

Mimsy, if you haven't refit YET...
It can pay to ask a couple of different sources for a "request for proposal" or "request for bid" and let them offer you a package price for the complete system. AND as part of this, you write a simple spec (i.e. all equipment must be fully interoperable on NMEA 183 or 2000, etc.) so that if the bits don't play nicely together--the vendor has to come up with the fix.
Most vendors will also come down a bit more in price if you mention "we're doing an extensive refit" because they want that business.
If you can, also use a credit card that offers an extra year above the manufacturer's warranty. That can be a nice bonus when something does go south.

[witzgall]

Whatever I did, I would make sure that the devices were on a NMEA 2000 network.

Chris