Great camera! My most used MF camera in recent shoots.
I love the 210mm 4.0 lens. This is similar to a 135ish lens on a 35mm camera. I don't have one, but I am borrowing one, and I LOVE it. IMHO, the only thing it could benefit from might be some extension tubes, depending on how you plan to use it. They are inexpensive lenses too.
The good-ol' 80mm 2.8 is a nice one as well, and also cheap. If she shoots in low light, I would splurge and get her the f/1.9 model and some Delta 3200, since they are not all THAT expensive for what they can do.
I love my 55mm 2.8. This is like a 35mm lens on a 35mm camera. They are also inexpensive.
I would like to try the 45mm next. Something close to a 28mm on small format would be nice.
If she uses fill flash at all, or combines flash with available light for any other purpose, I would consider the 70mm or 150mm leaf shutter lenses. The 70s are very inexpensive, but might be a sort of odd focal length for mixing flash and ambient light.
As for what I like to shoot with the camera, I would probably pick the 55mm if I had to just use one lens. If all I shot with it was low light stuff, I would pick the 80mm f/1.9. I usually take the camera out when I want a sharper 11x14 picture than 35mm can give me, for more static subjects like landscapes, cityscapes, etc. I do, however, use it hand held, and they are great for this. I also use the camera a lot for live music with the f/1.9 lens and Delta 3200 or a color 800 film. I love the teles for landscapes and portraits, and the normal and wides for hand holding.