Mary Wollstonecraft - She wrote the book A Vindication of the Rights of Women and paved the way for basic human rights for us.
Vindication is pretty cool, and it is certainly one of the most well-known feminist writings, but I find the text a little dated in terms of values expressed. And it's not really fair to say she paved the way, at least not alone: The Book of the City of Ladies. by Christine de Pizan is certainly older (and a better read).
william shakespear, by far best writer, playwright and poet world has ever seen.
By far? I don't know, I like John Milton... ah, but my heart lies with you, at least in part: The great artists inspire me as well. Vergil, Homer and Vyasa are my big three. But still, I don't find much inspiration in historical figures. I find more in the real people whom I've met.
I'm not entirely sure how to define 'inspirational' for myself; I wouldn't really say that any figure past or present inspires me too much.
As a Brit I could mention someone like Churchill but despite doing great he had many flaws. Darwin could be inspirational; but he spent a long time studying barnalcles; definenlty not something to inspire me.
I read the Qi book of the Dead a while back and was engrossed by reading about richard Feynemann. He did an amazing job in physics and did it in his own way. Which seems to be a good way too look at life.