Take your time and do your research. This includes eBay listings for mobos, cpus, and cases. Many mobo listings include a link to the manufacturer.
Even if you don't shop on eBay, it is still a good place to look around.
I found memoryonly.com and internetishop.com via eBay. My RAM is from the former and my 15 inch TFT flat panel monitor is from the latter. Even my cdrw drive is from the latter.
Even a midtower with lots of drive bays is a plus, as it gives you room to expand. My system is in a 12 drive bay full tower case (Internetishop happens to sell the exact case), and I currently have 8 drives in it, with 2 eide devices available, and 2 extra bays.