Brasas: Poland is definitively a great destination for anything related to "medievality". I think I have a tourist map somewhere dedicated to castles only - the kind with little images all over the place, not something you'd use to drive somewhere - and the thing is packed.
I love those illustrative tourist maps with pictures and abstracted dimensions, somehow I find them more useful than regular maps, plus they remind me of the maps they use in medieval movies. I traveled all over Egypt with a map that just had pictures, though Egypt is a special case, you only need to follow the big river, can't really go wrong much..
Brasas: It's also not an expensive country to visit, especially if you're on any kind of swiss or german payroll, or even benefits, so I'd suggest putting as strong lid on your urges to enjoy this visit for what it can be, and think of it a a recon for something more?
I'm freelance so neither on a payroll nor reaping any kind of benefits. At the moment, I'd make more money if I was on social security.
Brasas: Heck just the fact you'll get the drive to Malbork would be enough for me to jump on this, that place is not exactly easy to reach unless you get on a tour or have a car rental - I'm sure there are buses but for that you'd better speak some polish or know someone. It's not the kind of castle around which a city grew, like the one in Krakow which you can just walk to from the center. In fact the same applies to many other castles.
Bottom line - the logisitics of visiting the cities vs visiting castles are not really the same. What are you thinking in terms of logistics now that you actually have more options than you can fit in your time?
I'll have to skip any place that is not easily accessible via public transportation, even if it's a super interesting destination.
You are right about Malbork, the simple fact that I already have a ride to go there should be reason enough to go to Poland. I think Malbork is the Himeji of Poland, no way around it!
Ghorpm: I would advise you to make this trip and then perhaps in future - another (longer!) one. You see, I usually work abroad so I spend my vacations in Poland and I'm using this time on intense sightseeing. I think I've visited every single place that was mentioned in this thread + many, many more and yet I still have a feeling that I haven't seen even 5% of what this country has to offer.
A short trip is better than none and if you spend your time on planning and dreaming you won't go anywhere ;) So really, use this opportunity (as Brasas said - car trip to Malbork is already a huge advantage!) and then return to Poland in future!
I agree 100%. When I'm in high operational mode, I don't daydream or plan much, I just do it and talk about it later once I'm back home. My usual modus operandi used to be to just buy a flight ticket (one way or round trip) and once that step is taken, I worry about details later, if at all. When I'm in low operational mode, I need to push myself to do groceries even, and the grocery store isn't in Poland but 5 minutes from my house...
zeffyr: Let me add little, but charming castle in Kórnik, just few kms away from Poznań:
http://www.kornik.pl/Welcome_to_Kornik/Kornik_Castle/
And a little bit further, Gołuchów Castle:
http://david-polanddavid.blogspot.com/2008/09/gouchow-castle.html My browser is gonna crash from all the great suggestions you guys are making, thanks so much!