Rogue all the way!
I had to vote rogue.
First of all, it's the class with the most skill points, and (to me) the most interesting skill set. When the party needs a scout, it's you (hide, move silently). When you walk into a room, you're the one who is going to notice stuff (spot, listen). Need to get in somewhere? That's me (open lock, disable device). And everybody depends on you for safety in trapped areas (search). In any kind of exploratory mission, you're the king!
When fighting against humanoid opponents, a rogue can often outshine a fighter. Your to-hit is going to be comparable or within a few points, and you will usually have more attacks (two weapon fighting). And while a 9th level half-orc barbarian with strength 22 will be doing 2d6+14 = 21 or so with his greatsword, I'll be doing d6+5d6=21 or so with my shortword, as with tumble I can almost always be flanking somebody. (Note that both those examples are somewhat-min-maxed, but neither super-duper-gamed up.)
To me it's great.