Oh, so you've already ordered it? In which case my answer in your other thread
may not be terribly helpful!
Anyway, as for electronics . . .
A chart plotter is by no means essential. Nor is a GPS for that matter (how quickly we come to rely on things!) but they are so cheap that it definitely makes sense to get one. Or two!
In fact I would suggest that you go for a Garmin fixed set, and a cheap Garmin 12 handheld as a backup. If you're going to rely on GPS (and you will!), then it is worth having two . . .
I really like the Garmin stuff, and it has always worked well for me. On Phoenix I have a 120 (fixed), 75 (old hand held, mounted on console) and a 12 (handheld backup). Going round Britain a couple of years ago we had more GPS's on board than watches!
Make sure that you pick on with a large, clear display for your main unit, that's probably the single most important feature.
Fish finders? I can't help with that -- I've never used one! I would like a forward looking one though, for creek crawling . . .
Watever VHF you get, make sure it's really waterproof. There are a few on the market now, but I don't know which is best. The last one I bought was a Humminbird which used to be the only real choice, but I think there are better options now. Alternatively get a regular VHF and mount it in a waterproof enclosure from DS Developments -- it will cost at least as much as the radio, but it's the only absolute guarantee of keeping water out (and that includes the "waterproof" radios too!).