Most of the models over 250/300 should at least have a jack on the back for a pedal or two. They should also include MIDI jacks as well, so you don't really need to spend the extra for one with a disk drive. Does she have one currently? Keyboards are pretty subjective, so you should try to get one where it can be exchanged for a different model if necessary.
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If she plays classical, she'll almost definitely want a pedal. You may also want to go for 76 keys instead of 61--that may be a bit too limiting for more complex classical works. With the octave shift functions available, she can probably get by with a 76, but a full 88 is always ideal.