My father (75) bought a 16GB Nexus just this weekend. I also became quite addicted to the thing while he was staying with us but I managed to convince myself that 16GB would probably be too small. Two days later and I hear about the 32GB model - I can't think of any reasons not to buy one now - can't wait
PS My father won't be exchanging his 16GB for the 32GB as he's very happy with what he has.