As you are probably aware by now, Warsaw has not one dominant architectural style.  This is due to to the wars, destruction and therefore rebuilding that has had to happen (especially after WWII where 80% of the city was destroyed) and where different town planners and architects meet. 

In summary, Prague or Barcelona it ain't but seek and you shall find interesting things.  Open your eyes, go off the beaten track and you'll be amazed at what you can find.

Here is a selection of photos showing the different kinds of styles on offer (old and new).