from a quick peek it looks like the hd300 is a HTIB set released by klipsch. i remember seeing this or something similar when i was picking out my own speaker set. i didnt go with it because it wasn't quite what i wanted in a set.
i ended up buying the big brother to the set.... the klipsch quintet IV speaker set and a 450w. if the hd300 is anything like its more expensive cousin it should be pretty good but give it a listen first. i think bestbuy has them on display. one thing of note: i tested out the PC speakers klipsch makes, the promedia 2.1 and they were not up to snuff.
dont know anything about polk.
all the logitech speakers i've ever owned, and those people i know have owned have sounded great for the price. i still have an old 5.1 set around that works and its over 6 years old.