I've played lots and lots of RPG's in my life, and I can honestly tell you I'm positively fed up with the random encounters; they really get on my nerves.
Sometimes I've even stopped playing an RPG solely because of the excessive random encounters.

I've only played one single RPG with a perfect battle system: Secret of Mana for the SNES.
In this game you wander around and fight enemies, Zelda-style, the only difference being you get EXP points and whatnot for defeating the enemies.
You can walk past them, you always see them, you can whack them for a while and then run away, and there aren't even any screen changes.
I ended up fighting much MORE in this game just because it was always optional.
It is indeed like a Zelda game.

This is a perfect battle system, and I fail to see why it isn't used in other RPG:s as well.
Nobody likes random encounters (at least nobody I know of) and still they exist.