Commander Shepard is perhaps one of the most powerful - and empowering - females on this list. Not only can she look as realistic, unrealistic, beautiful or... homely... as you want. She can also be as flirtatious or as dangerous as you want. But we're not here for her social life. Instead, we're here for the weapons of mass effect (get it?) that are at Shepard's disposal.
In example, Shepard is capable of using a number of weapons types ranging from space pistols, to shotguns, assault rifles, and snipers. However, it's Mass Effect 2 in particular that Shepard carries around the most heat. Weapons like the M-920 Cain nuclear launcher or the M-490 Blackstorm are literally weapons of mass destruction. This puts her above Nova Terra since she can pretty much launch a miniature nuclear bomb at any time.
While this is great and all, Shepard herself is not exclusively a woman, nor is she a character of her own. Since players have to decide what kind of woman (or man) Shepard is, she gets placed at #3 on this list.
But hey, for any fanboys or girls she certainly earns my #1 spot as the most fun at parties though, especially when Wrex and Grunt are around.