About reliable, i am very happy with Supermicro product... they are not cheap but my computer is running 24/24, 7 op 7, and for the last 6 year, without any problem...
I have buy directly he case with everything ( http://www.supermicro.com/products/chassis/4U/745/SC745TQ-920.cfm ) at around 300 euro... but they sell part too... some sample here for mid tower ( if you have a ATX tower )...
If you are a heavy computer user, best put a little more money in your PSU for a high efficiency power supply, at lest a 80+ model... low end PSU convert a lot of energy in heat, not really useful and costly in the long term...
If you are really short on money, and not too much ashamed, try a container park ( http://www.gentblogt.be/wp-content/uploads/2008/04/200804_containerpark.jpg )... my last keyboard and mouse come from there... some people throw away a full computer when maybe only one memory module is defect... will only cost you 1 or 2 beer bottle for the guy who watch the park...