I am currently running my node using a 400 Watt PC, and it's starting to show in my power bill :p
I purchased a mini pc which runs at virtually nothing and I leave it on 24/7 and it's ticking along nicely generating those coins.
You can pick up the new VivoMini UN42 for around £199 UK and this runs at only 6.5w
Here is the link https://www.asus.com/uk/Mini-PCs/VivoMini_UN42/
That is a REALLY cool PC for long term use, but its pricey, is way too powerful for just an SLR Wallet program, & it doesn't even have a monitor that I can see.. here is an HP made laptop that has all you need and arguably runs at an even lower power consumption rate when the screen and all other programs are disabled >>
http://www.amazon.com/HP-11-r010nr-11-6-Inch-Notebook-Processor/dp/B015CQ8SGE/ref=sr_1_1?s=pc&ie=UTF8&qid=1447958738&sr=1-1&keywords=laptop
Not as cheap as a Pi, but getting there...As notebooks get cheaper and more power efficient I bet we will even see some sold WITH solar panels right out of the box
Thank you guys! I might just try and run the wallet on a raspberry pi still a lot cheaper than buying a noteook or a mini pc!