Monk combos best with a class that allows it to boost its damage-per-hit. Fighter is decent for that, but rogue is better.
Fortunately, thanks to the miracle of gestalt rules, you can have your fighter cake and eat it roguishly!
Normally, Return to the Elementally Oversized Ancronyms is something of a meatgrinder, but with gestalt characters, it could either be much easier (if your DM uses the adventure as-is) or just plain brutal (if he ups the baddies in accordance with UA's gestalt guidelines). In any case, I don't feel the slightest compunction against providing you with a cheesy trick to improve your chances.
Monk 1/Fighter 1
Monk 2/Rogue 1
Monk 3/Rogue 2
Monk 4/Rogue 3
See the trick? By staggering your monk and rogue levels, you get +1 BAB per level all the way to 20th, but you still get full sneak attack and flurry of blows progression.

To the best of my knowledge, gestalting is the only way to get 1:1 BAB and Greater Flurry pre-Epic in 3.5.
The Eberron feat that lets you use swords (meh) or spears (woo!) in a Flurry of Blows is a nice pickup here. It's sooo easy to flank with that lovely longspear, and if they get too close - smack 'em unarmed!