drome,
I am not the most current on what's out there, as I sold my boat 3 years ago, but here is my $0.02.
We were divers, so finding the wrecks was most important to us, which when fishing, structure is important.
I had 2 GPS units, Both Garmin. One strictly GPS, the other GPS/Map/Fish finder. Also had a Si-Tec 106 color fish finder. The color unit was great because it would indicate bottom conditions (mud, sand, rock etc)
A hard mount VHF radio, plus a back up hand held is probably the most important piece of electronics. Radar is nice if you are out early in the fog. We also had an EPRIB and a life raft, but we were going a good distance off shore.
Good deals can be found on ebay for a lot of this stuff, but make sure it comes with antenas and transducers, or that good deal becomes expensive very quickly.