Would also like to mention that on April 30th of each year its Koninginnedag. Its the largest national holiday in the Netherlands and while its great fun to see and join in with it does mean that the population of Amsterdam swells to something like double its size and also the streets are packed and everywhere is full. Its like one massive street party.
If you are planning on getting there a couple of days early I'd strongly suggest to not arrive on or before this date. Mainly as a) accomadation is often booked up and b) it makes getting anywhere or doing any proper sightseeing near on impossible and c) it is also blooming expensive
Some areas are less busy and it can be a lot of fun but if you dont know the city or anyone there it can be a real pot luck shoot where you end up and what you do.
I'd advise arriving a day or two after this and therefore missing the crowds and the mayhem and also the accomadation won't be as full. If you want to have a bit of time there, stay on after the gigs rather than arriving too soon before.
I used to love Koninginnedag. We'd go out about 10pm on the 29th and not make it home till about 5pm and the 30th
People start selling stuff on their doorsteps and on the streets from midnight (in residential areas usually from around breakfast time till mid afternoon on the 30th) and the city centre is jam packed with people, street performers, bars with DJ's and parties in the streets, food vendors and more. Its a great atmosphere but often we would just get swept along in the crowds without being able to really choose where we wanted to go. And trying to get served at a bar or some place was hellish and often meant no chance to sit down. But then we usually partied the night away, went to the Vondelpark in the daytime as its set aside for kids events and stuff and has a really great atmosphere on the day with lots going on. Or else to a party or rooftop BBQ or some such.
Times like this I really miss Amsterdam.
Will dig up some good places to check out and so on for those visiting