Without any specific requirements, I can recommend the following recorders:
Marantz 660 - great 16bit recorder, has XLR inputs.
Fostex FR2LE - can be had fairly cheap ($450) on eBay. 24bit, XLR inputs.
Edirol R-09 - cheap pocket sized 24bit recorder. Only has mini-jack inputs. Input jacks are known to be fragile, but are an easy fix.
Marantz 620 - alternative to the Edirol
Sony PCM-D50 - alternative to the Edirol and Marantz 620
I would not recommend the Zoom H2 or H4 units. The preamps on those devices leave a lot to be desired. Instead, it's worth the extra money for the above mentioned recorders. All of these can be found very cheap on eBay or, as I mentioned above, taperssection.com.
I'm assuming these recorders will be at the max of her budget. If not, I have several other recommendations.