I used to love BB; they do the most damage but they do die rather quickly (lower HP than Ft, and much lower [and buggy] defense).

I think the easiest run I had was Ft/Ft/WM/WM. The Fighters can absorb damage like none-other and the WM can keep them alive. The lack of Fir2/Lit2 early on is a bit painful, and the lack of Fast or a BB does slow down the damage, but you get items that cast those later on.

Replacing a WM with a RM gives you access to black magic and more melee damage, so that's an option too. RM are money hogs early on though, so YMMV

My favorite looking character is the BM, but they become worthless towards the end of the game as anything but machines for buffing your melee characters. Sure Nuke is a great spell, but unless you overlevel you get to cast it once or twice in the final dungeon, which is kind of underwhelming.

All the hating on BB aside, 4BB is the most straightforward party. Just don't get the rat-tail, as BB get worse after turning into masters and don't forget to look at the status screen after each level up (see black-belt armor bug). You will use more heal potions than other classes, but you can afford them since they are so cheap to equip (Masking-tape + A button is your friend).

If you want to get a good feel for each classes strengths and weaknesses, play through with all 4 of that class. It's not obvious until you try it, but 4WM is *much* easier than 4BM, and 4RM is great until you get about 3 orbs lit at which point it becomes mediocre.