Schönbrunn is a palace seen for itself. The Hofburg contains several museums (I recommend the Schatzkammer) although some apartments may also be visited.

http://www.flickr.com/photos/mksfca/4206883892/in/set-72157622927111169

Just my thought on Wawel Hill in Krakow. You can walk up and around the grounds for free. To get inside we had to wait almost an hour just to buy our tickets. After all that, both of us felt for that it just wasn't worth it. There are some large rooms, but the invasions and pillaging of Poland over history is the most obvious thing to see because they have so little to display to the public. It was sad, as we've seen many palaces. If you have Polish ancestry, it may be worth it because of that. Otherwise, keep to the outside and just imagine what you may have missed inside.

I agree about Wawel castle. My favorite thing were the 30 heads suspended from the ceiling in the State Rooms. Apparently I was supposed to pay more attention to the famous tapestries but forgot all about them.

If you really want to see Wawel castle then reserve your tickets for a future day. There's a special office for making reservations with no line. You then pick up your tickets on the day of the tour. Complete directions for doing this are in my trip report - click on my name to read it.

There's so much in Krakow and so many more interesting sights to explore than Wawel.

So where is Schatzkammer???

See this link for info on Schatzkammer:

http://www.aboutvienna.org/sights/hofburg.php

Tinydancer and Adrienne, What are some other recommended sites in Krakow? Thanks to bettyk

Konopiste is wonderful and full of history. Krivoklat is not too far away and makes a great day trip from Prague. Krivoklat has the advantage of having a great restaurant nearby.
http://www.jeremytaylor.eu/photos/konopiste-castle/
http://www.jeremytaylor.eu/photos/krivoklat-castle-in-the-czech-republic/

We went to Krakow as a base to visit Auschwitz - Birkenau. But when I saw the raves about Krakow on the travel sites, we extended our stay for 4 nights. We LOVED Krakow! Totally unexpected!

It is fully intact as it wasn't bombed during the war, and there are many, many beautiful buildings. The main square is nicer than the one in Prague or Dresden. The feeling is wonderful. Everything is done with care, and attention to details. Even the horses and carriages appeared to be more elegant and beautiful. We were there in August, and there was a market in the square with many traditional crafts for sale, as well as entertainment. Very lively everywhere.

The people are friendly, and really try to please (but eat in Polish restaurants as Italian is, well...Italian!)

There is Schindler's Factory which is a Holocaust Museum & history of Krakow under the Nazis. The Jewish Quarter is interesting, but not very uplifting as one can imagine. I believe the Synagogues are manned by Poles, not Jewish, so not sure if that matters.

Not sure if you planned on visiting Auschwitz, but I highly recommend it. Over a million people a year visit and it is a memorial and a museum. I was amazed at how much I didn't know or understand about the camps. There are many tours to Auschwitz. They kind of keep a quick pace, but our guide was still good.

There is the Wieliczka Salt Mine you can also take a tour to. We weren't sure if we should go, but we did and we were very happy. It's something you have to see for yourself and it is really amazing. Here's a link with reviews and photos. Everything in the mine is made from salt. Highly recommended: http://www.tripadvisor.com/Attraction_Review-g277819-d284943-Reviews-Wieliczka_Salt_Mine-Wieliczka_Lesser_Poland_Province_Southern_Poland.html

The main square also has a market building, the Cloth Hall, that has all sorts of treasures. The square is the place we had breakfast and dinner most days except at our hotel one night.

Here's a link to what to see: http://www.tripadvisor.com/Tourism-g274772-Krakow_Lesser_Poland_Province_Southern_Poland-Vacations.html

Hope this helps!