Sure, statue form isn't a requirement for the large races, but it's an improvement. Freezing cloud isn't a requirement either, but it's an awesome spell. Getting statue form on a troll is also very much worth the investment (it's slightly better for troll since trolls will be using unarmed and can keep their claws, but it's also pretty decent for Og). Most of the obvious races have been covered, but what the hell, here's a list:
Best:
Octopode, felid
Amazing:
Troll, vine stalker, merfolk.
Unusual but interesting cases:
Tengu - even though their aptitudes for trans/earth are terrible. Kobolds, halflings, and spriggans: all of those are races which have terrible hp and would benefit from +30% hp (also a main reason for vine stalkers). Small races also have terrible melee weapon choices, so unarmed is great for them, although this is counteracted by terrible UC aptitude (halfing and spriggan -2, kobold is 0 though). Tengu are natural unarmed fighters (+1, aux attacks), but getting statue form itself is a larger investment than normal.
Demonspawn might be in this category if they get the right mutations (claws especially, but other aux mutations that make you lose boots makes statue form better too).
average:
All the other standard races. Note that while this is just 'average' I consider the average case to 'awesome time to go statue form' and this is not in anyway meant to discourage human, demigod, formicid, or demonspawn statue form characters. They're great. Play them
Below average:
Naga, Centaur (melding bardings sucks, losing naga scales), Vampire (unless you have a plan for always being fed). Of course the races that can't use it: gargoyles, mummies, ghouls. It can still be used on Nagas/Centaurs but the AC just isn't really there - it can boost your damage, but so does blade hands, so unless you really, really can't handle a torment, there isn't much point. That said I've still done it because why not
So really the big omission from the thread so far was vine stalkers. Seriously, try it out. -30% hp is their only weakness, and yes, you still bite in statue form. Obviously the race is very powerful to begin with so you certainly don't *need* the extra hp, but once you have it, my god