Find out what body style of electric she prefers, and that will help narrow down the options. Transitioning from acoustic, she'll probably be more comfortable with a fixed bridge electric, but she may want to try a floating bridge. The suggestions already made here are good ones. I'm a Les Paul guy, so I lean toward the Epiphones. You can get a Les Paul Special II for $150 brand new, and it's a well-built, quality guitar for the price. Fender Squier are good beginner guitars, too, though, and Yamaha makes some really good budget guitars as well.