I would use built-in lists for any lists (uniform variable-length sequences of objects).
I would use namedtuple-derived classes to store data with known fixed sets of named fields. It's like objects, but immutable.
So you'd have your text.tokens[3].part_of_speech == NOUN, but won't have text.tokens[3].part_of_speech = NOUN. Immutability is often useful at preventing a whole class of errors, though.