I'd go to a store and let her handle a Nikon, just to see how it feels and how easy the menu system is for her to go through. I prefer Nikon myself, but I know plenty of people that use Canon and love them. It's really just whatever she likes. They both do well.

I realize that she's not heavily invested in Canon at this point, so if she wanted to change now would be the time

You can find deals on Craigslist and Ebay, if you know what you're looking for.

I found this.

http://www.walmart.com/ip/Nikon-D5100-16...e-Bund/20549893

She already has the standard either 18 or 28 to 55 mm lens and the 75-250 for the Canon but she VERY rarely uses the small lens.

My most used lens is an 18-70mm, but I normally am shooting people or scenery. I carry a 70-300mm in my bag, but I don't carry my pro lenses around normally. Just too heavy to haul around.

What do you think of that two lens kit I linked to? Would it be better than her Xs with a better lens?

That would be a heck of a kit for her. The lenses are both VR lenses, which are Vibration Reduction. Basically, helps eliminate shakiness. It's a nice feature.

BUT you can also buy IS lenses for Canon, which is basically the same thing. If she's happy with her current camera, you could go that route.

The 75-250 she has is an IS lens. Maybe by learning these new functions she will get into it more. How would a 1.4 or doubler work with that setup? Would using the new functions overcome the light reduction that a multiplier would bring?

Just have to take the ISO up a stop or two. The 1.4 reduces light by one stop, the 2x by two stops.

In other words, if she was using the 1.4x, she'd need to change her ISO from 200 to 400 to maintain the same shutter speeds and f-stop.