Which type of variation would you choose

10% taller - 5'6" feet tall -> 6'1/2" - that's a pretty big difference.
10% richer - almost no difference
10% stronger - not much difference - 1 month in the gym for an untrained person increases strength by 20%
10% heavier - depends how it gets allocated
10% fatter - huge visual difference - going from 18% bodyfat to 28% is huge
10% thinner - 18% to 8% bodyfat is a few year's worth of work and probably includes both lots of muscle gain and lots of fat loss.
10% smarter - rather big, nearly 1 stdev, worth a lot
10% luckier - hmm, might be great if there really is no such thing as luck (you would be able to beat the house at gambling, anyway)
10% less sleep needed - 8 hours -> ~7 hours/night. Pretty good.
10% faster runner. For most people, not a big change
10% increased livespan - 80 -> 88, not that great. Note this should be calculated based on current expectancy, not at birth.
10% increased maturity rate: at 10, you'd be like 11. at 20, you'd be like a 22 year old. Could be ok.
10% faster blood clotting. Hmm, not that great, there's already lots of variation there.
10% better vision. Would be ok, but there's already huge variation.
10% more ambitious. This would probably get you places.
10% better immune system - there's already tons of variation
10% stronger bones - already tons of variation
10% faster thought - this could add up to tons, depending on how intelligence really works.
10% bigger brain - could be a lot. There seems to be some relationship between brain size and intelligence.
10% more fingers - weird
10% more neural connections - might end up driving you crazy