I don't believe that there is a 'best' bike for commuting, unless we are talking about a mega commute with tonnes of k's to go. It comes down to personal choice really and what you want out of the bike .
Hills aren't any biggy. With a road bike or mountain bike Geared properly, you can climb anything
What kind of bike do you have now? How long is your commute? Road bikes in general are a lighter frame so you can get from A to B a bit faster