Creating a system you love shouldn't be difficult. The Acoustic Frontiers blog is here to help.
To size a power conditioner note the following: UPS systems are sized according to the maximum amount of power, measured in Watts (W), that they can support. All other power conditioners are sized according to the maximum continuous amount of current, measured in Amps (A), that they can supply.
The simplest way to determine the above is to purchase a Kill A Watt EZ Electricity Usage Monitor meter and plug all of the equipment into that. The Kill-A-Watt gives you both Watts and Amps. With equipment that consumes power dynamically such as audio gear you need to play a test signal such as pink noise through the system at the maximum volume you might listen to. This is because the power draw will be greater with a signal playing than without.
If you don't have or don't want to buy a Kill-A-Watt then you will need to look at the manuals for your equipment and add up all of the power ratings. Once you have these you can divide by 120 to get the current draw in Amps. For example a simple system with a CD player (40W) and integrated amplifier (maximum 560W) would consume 600W or 5A.
Nyal Mellor, Founder, Acoustic Frontiers