Gifts at ordination (or for other special events) should be marked by both appropriateness for the occasion and by a generosity of spirit.
Ordination is a deeply spiritual event, so gifts might include a new Bible, commentary set, commemorative plaque, etc.
A desire to be generous (depending on the size and financial ability of the church) might lead to the inclusion of funds for a weekend away, a night out, etc.
In every instance, however, it's most appreciated when gifts are personal and given in love. Instead of just a generic plaque, have someone design a commemorative piece of art that everyone from the church can sign. That would be treasured!