For electric, I've been running the same corded Rapala unit for about 10, or so years. It's gotten a few new sets of blades over that timeframe, but it's been dependable as hell even though I don't take very good care of it. Actually rides around in my door pockets 12 months out of the year.
For old fashioned fileting, I have a few different blades. The standard Rapala knife we all grew up with is by far my least favorite, shitty handle and hard to maintain blade. My fave is a blade that is only stamped U.S. Cutlery, I suppose it's 40 years old and has been sharpened so many times I am just waiting on the blade to snap one of these days as it's getting kind of thin. It's also my very favorite knife to debone deer because of its flexibility and edge holding ability.
All the rest do the job but are just another tool in the box for me.