Brake for the Buck

I'm assuming by "old style XT v brakes" he's referring to pre-2001. I have some 2001 XTs and they squeal like pigs rather than braking like they're supposed to. They just suck. Other people I've talked to say they've stopped traffic with an uncurable squeal that sounded more like brakes from a big truck, and that loud. Toe in, toe out, the only thing that fixed the squeal was using a different brake. And the squeal was the sound of massive vibration that didn't brake very well, while chewing through pads at an increased rate. Do NOT consider XTs, unless you can find some of those "older" versions that don't suck ass. If you want brake for the buck, I'll give you mine. They'll disappoint you, but for the price of shipping, I suppose it'd be hard to beat.

Buy Avid SD7. No silly parallel push... that's a gimmick with extra moving parts to wear out and develop slop...SD7 has just a very rigid brake caliper, and they're the brake that convinced me that there could be a difference among V brakes. Thay're amazing, and for the money, they're tip top. SDTi are literally the same brake, just with Ti hardware, which I'm pretty sure you can get separately, if you want to upgrade later.

Other things to seriously consider if you want power from your V's...

-Brake boosters. Yes, they really do help. Salsas are probably the best you'll find for the price... and some of the best you'll find period. Brake boosters reduce flex in your frame and your fork, which helps you put the power where it belongs... in the brake, which then applies it to the wheel. They also cut down on squeal for the same reasons.

-SD7 levers. (This is assuming you don't buy the set which includes levers.) The adjustability is second to none, can be done on the fly, and the higher torque settings will give you increases in both braking power, and modulation. It's a rare thing you can get so much more out of a system, without so much addex complexity. There's a reason people fall in love with avid.

-Better pads. Look at the dual compound block pads from koolstop. I say block pads over cartridge because they have more brakign surface, and they're grooved better to plow water away. The cartridges just don't have enough material to add all that extra work.

-Ceramic rims. Yes, I know, they're expensive. You said you wanted the most powerful setup. Once they've been properly broken in and after being given a nice coating of rubber from the first set of brake pads they chew through (and they will) their appetite for rubber seems to be sated, and the braking power is almost comparable to discs if you have the right brakes. My setup had avid SD7, salsa boosters, and Mavic D521 ceramic before I went to discs, and discs just seem to have more modulation. Just don't ever clean those rims.