Bitfenix cases seem to be pretty budget minded :
Bitfenix Merc Beta Steel Black ATX Mid Tower Case 3X5.25 7X3.25 1X2.5 *No PS* Top USB2.0 Audio - BitFenix - BFC-MRC-100-KKX2-RP
My last case was a fractal design which are pretty amazing if you are trying to build a silent case. Before that I had a CM Haf 932 but that is to much 'bling' for me now.
As for windows, while looking cool they always cost more and will not block out noise as well as a flat side panel would so you have to figure out if you want better silence or better aesthetics I guess.