If you will already be in Spain, then why not visit Barcelona? Or have you been there already? If you are the party type person, then Ibiza is also an option. The best time to visit the party island is in August! Paris is also great! There is alot of culture, many things to see, and the opportunity to buy some trendy clothes. I want to go back! Stockholm, Sweden is also a cool city! I took a cruise from southern Finland to Stockholm last September and had a great time. The city is pretty amazing. As for Brussels, I would totally skip the place. I was there for one night one my way to Amsterdam and I thought it was too long. I was warned of how dreary the town was before going there, and now I totally agree....SKIP IT! Amsterdam was fun! The people are so frickin' nice and I like all the canals in the city. You probably know that smoking is legal there...very fun! My advice...pick a city that will keep you entertained. Everyone likes to see and do different things when they travel, soooo do your research. I highly recommend skipping Brussels! Hope this helps.