Having used practically every nail polish remover under the sun I can safely declare that my favourite is the Bourjois Magic Nail Polish Remover:
Can I start by saying this smells super yummy? It reminds me of something from my childhood but I can't put my finger on it! This is acetone free but you wouldn't know it as it's so effective at removing nail polish, even glitter ones! It does take more than the 1 second it claims on the bottle- maybe 2-3 seconds but I am not complaining! Just put you finger in, give it a twirl and voila, nail polish is removed! It takes longer for glitter polish but that's understandable. It's convenient as you can easily travel with it and there's no need to find cotton pads and easily available from most places (Amazon, Boots and Superdrug, £4.99 from all). After this I could not go back to using conventional nail polish removers!
If for some reason you can't find this one then Maybelline has also launched their version (for some odd reason it's not on the Boots, Superdrug or Amazon websites yet, but I have definitely seen them in-store and I picked up mine from Boots as part of the buy one get one half price offer, otherwise I think it's similarly priced to the Bourjois one).
I have not yet used this one, but it appears just like the Bourjois one and is also acetone free. It smells nice but Bourjois wins in the smell department :)