I can take like ~50 pics (high res) with my 128 mb memory on a 4 megapx. camera. So 512 mb is truly enough.
Hmm.. I cant see why the S1 costs alot more than the A80. The only thing I see right now is that the S1 got more zoom than the A80, but on the other hand the A80 takes shots in 4.1 megapx. and it also weights half as much as the S1.
[edit] oh.. the S1 got some good video recording.