Originally posted by: Zepper
Here is the results of a search on Newegg with your criteria (black mid-tower, no PSU, side window, price $50-75):
Case Search. From those, the Kingwin 523, the Tt Swing and the Aerocool AeroEngine seem to stand out to me. The Kingwin would probably be the quieter of the three but you'd have to rig some rubber mounts for the HDDs and fans to equal the Sonata. None of the three have rubber HDD or fan mounts like the Sonata. jab-tech.com sells nice rubber fan pins.
You can get the Centurions with side windows. But the price usually goes above your bracket. The Kingwin 523 is identical to the Centurion case inside, but with a side window and a door (can be had with blue or red lighting which can be unplugged). Directron shows a case similar to the Superflower under the AMS brand.
Another option, if the Sonata II meets your needs otherwise, is to have a window installed. coolcases.com puts windows in the Compucase 6A19 routinely - its side door is nearly identical to the Sonata, so it should be no problem for them to do that for you.
If you can stretch the budget a bit, the Silverstone Temjin 4 (SST-TJ04) looks like a possible.
.bh.