Where to go for my Holidays?

[Superdude]

Now, I've recently booked a 5 night stay within Amsterdam starting on May 31st and getting a cheap flight back home afterwards.

Now here my problem. I can just fly into Amsterdam on the 31st and be done with it however I really want to explore somewhere else before hand.

Any ideas for cities in Europe to visit?

I am on an extreamly basic budget and will be sleeping in hostels. I also need cheap transport to Amsterdam afterwards