Night life -
Goto Leidseplein, there are lots of pubs over there (my favourite is the Irish Pub). If you want to goto a club, the 2 best ones are 'Jimmy Woo' and 'Club Air'.
If you enjoy cocktails and you're looking for a nice place to bring a girl to then I highly recommend 'Door 74', they make the BEST cocktails and their service is EXCEPTIONAL. Before you go you have to make reservation 'on that same day you're going', call this number +31634045122, leave a message and your number and they will call you back to confirm your reservation (can take hours before they call you). Their address is: Reguliersdwarsstraat 74 (Very close to Rembrantplein).