i was facing the exactly similar situation. after all the brain-storming it boils down to this:
join bank PO only if you love banking and finance and you are sure dat u want to make a career in it, coz frankly speaking banking job is tough these days and it'd be hard to hang on to it if you don't have a long term perspective. other wise excise is cool, except for the slow promotions, but i guess one can live with dat. :)