This is she, if you want to sound like most people.  Nice extra bonus: it is also 'proper English.'

Same here. I usually just respond with "Speaking." Quick and to the point.

There might be male female difference here. A woman will tend to say more than a couple words at a time.

Many times, when I get a call like that, it's coming from someone using a list. Since I tend to use my initials rather than my given name, such a caller will ask for me by my last name.

I've been either blessed or cursed (depending on the need of the moment) with a name that most people mispronounce, I'll take the opportunity to correct them. "May I please speak with Mr Dranny?" "This is Mr Draney." That's a little more polite than "It's pronounced Draney, you telemarketing imbecile!"; they can note the correct pronunciation and adjust it going forward.

It also affords me the opportunity to blow off some callers altogether: "Dranny? Nobody here by that name."