I've been using an old PC (AMD Athlon 2400+ XP [2Ghz]) with 1.5GB ram and a 420W PSU (I think?) for a while now and often wonder how much juice this is sucking being on 24/7. It also has a DVD burner and 2x IDE HDD's.
Can anyone provide any insight into this? If it's costing me $20 a month or less I will leave it on, if it is likely to be costing more I will swich it off when it is not in use.