Most of us gamers enjoy the classic "Overworld and Battle Map" RPGs. So I would like to know what you think of different RPG battles such as the classic random encounters with enemies and those RPGs in which touching an enemy brings you to the battle field. Which do you prefer and why?

Feel free to elaborate.
In my opinion, you do whatever suits your game best. If you're going for a classic RPG, you'd do the random encounter setup. If you're going for a typical MMO, you'd do what they do, etc etc. Just make it fit your game.