there's so much diversity in snakes species and morphs, there's something for everyone including your GF. if she likes the slender bodies u two can get one of the bigger Colubrids like somekinda Pituophis like a Bullsnake. or a smaller, leaner Pythons still like a Children's, Spotted or Savu; or a Dwarf/Island Boa.
either way, i look forward to seeing the new addition!