I prefer V brakes over maggies, if setup right they can be plenty powerful. I wouldn't get XTR in my experiences because they have parallel push and all the linkages become loose overtime making the brake feel poo. Same with the avid arch rival, shimano xt and old lx. Stick with the 'normal' calipers like SD5, SD7, Deore, New LX, Ultimate. If you have the money than get ultimates because they really are the best. But if not its more important to buy good levers and good housing. For levers, XTR is really good and so are XT's, XTR's last longer apparantly. I prefer the feel of shimano levers over the avids because they have a thinner blade. Having said that the avid ultimate lever has a different blade to all the other avids and feels the best and is the best lever you can get but it cost a bucket load. So I would just get XTR's if you want to keep the cost down Housing, I've never tried nokon but odessey linear slic's are awsome, really makes the brake alot stiffer, I've been using it for about a year now and haven't noticed any sponginess. I prefer it over my xtr housing, plus they come in funky colours. Right now I run SD5 calipers, RB booster, Ultimate levers, linear slic's and Heatsink whites without a grind. The power is much better than my maggie with plazmatic pads. I've never needed v brake adapters so i don't know anything about it but have heard the new heatsink ones are really good.