I can personally recommend the Coolermaster Elite 335 - I use a drive bay converter to fit 4x 3.5" drives into 3x5.25" bays, giving me a total of 9 HDD bays (I use this case for a file server). It has good build quality (as all Coolermaster cases do) and isn't too flashy. You'd struggle to fit any kind of water cooling in there, but for air cooling you can fit an optional case fan at the front of the case. It's a bargain at £30.
Someone earlier said that it's just a box and it doesn't matter. I disagree. Poor case choice makes upgrading much more difficult down the line. If you plan on opening up your case to upgrade parts several times over a year, you might want to consider HDD bays at a 90-degree angle to the case side (or 'window') - this leaves more space for graphics card over-hanging the motherboard. It will also make it much easier to swap out hard drives, should you need to (I do this more often than I thought that I would). Good cable management (i.e. being able to route cables round the back of the motherboard) considerably reduces clutter and makes working inside your computer much easier, mainly because it's easier to see what's going on.
The 335 doesn't feature either of those options, but it is a £30 case after all and does feature rare build quality at that price.