You should have made it so the poll could have multiple options instead of one! I love Polish composers, generally speaking. As far as the Romantic era goes, I like Xaver Scharwenka and Chopin the most. However, in the last 100 years, I believe Polish music really took off, starting with Karol Szymanowski. Then composers like Krzysztof Penderecki (spelled correctly here), Andrzej Panufnik, and Witold Lutosławski really brought Polish music to a larger audience, with Penderecki still alive and composing (now in a neo-Romantic vein, as opposed to his early avant-garde works). I would say that Lutosławski's 3rd Symphony is one of the most significant pieces of the whole 20th century, and it was actually very popular when it premiered in 1984, and it is still popular and studied to this day. Of course, there are many minor Polish composers that have made their mark over the years. I would argue that Scharwenka shouldn't be minor (in agreement with thal), which is why I initially included him alongside Chopin. Others like Melcer, Moszkowski, Sigismond Stojowski, and Grażyna Bacewicz (from the early 20th century) weren't really movers and shakers, but still had nice music. All in all, I wish Polish music as a whole had wider exposure, especially the composers I mentioned.
Btw, you might want to fix the typos in your poll.