It's not just the President who died, apparently the entire higher Polish Armed Forces Commanders were on the plane as well
-Chief of the General Staff of the Polish Armed Forces General Gagor
-Commander of Army General Buk
-Commander of Navy Admiral Karweta
-Commander of Air Forces General Blasik
-Commander of Special Forces General Potasinski
-Operational Commander of Armed Forces general Kwiatkowski
-Commander of the Warsaw Military Area general Gilarski
-Ryszard Kaczorowski, the last President of the Polish government-in-exile
-Jerzy Szmajdziński, Deputy Speaker of the Sejm
-Władysław Stasiak, Chief of the Office of the President of the Republic of Poland
-Aleksander Szczygło, head of the National Security Bureau
-Paweł Wypych, Secretary of State in the Office of the President of the Republic of Poland
-Mariusz Handzlik, Undersecretary of State in the Office of the President of the Republic of Poland
-Andrzej Kremer, Deputy Minister of Foreign Affairs
-Sławomir Skrzypek, President of the National Bank of Poland
12 members of the Sejm(lower house of Polish parliament) also on board.
That's alot of high ranking people to lose at once. I mean most of Polands upper echelon(civilian and military) have been lost.
EDIT: wikipedia article has the
full list of VIPs on board.