Do not waist your money on Polk speakers. Especially if you are going to get those really nice components, ie, the 3490 and HD990. Those Polk speakers will not let the benefits of improved sound quality come through with those nice components that you purchased. I mean that you would be better served by going with a used pair of speakers from A-gon or Ebay, or look into some of the internet direct companies such as Ascend Acoustics, HSU, Chase, and you might even think about doing a DIY build.
If you go with a DIY build, you would end up with much better sound quality and spend a lot less money in the process. There are speaker kits that you can purchase from DIYSoundgroup and some others.