New energy efficient PC on order

I've been considering (separate from this electricity consumption adventure) getting a new PC. The current one is a few years old, big and bulky and I no longer have the time (or desire) to build my own.

Earlier in the week I noticed that my wife's machine (even older) was terribly slow in starting, responding and generally operating too.

I'm in the IT world and know a thing or two about configuring PCs and removing programs/files on them to speed them up. I couldn't seem to make much headway with it.
Also, my son was using the machine more and more to view Lego sites, Youtube of Lego Star Wars and other 'fun' things, and we wanted to get a bit more control over what he did.
Solution - get a new machine.

I don't need the world's best machine. Nor do I need one I can upgrade - a general purpose one will do. It's for my email, occasional Visual Studio, download of Podcasts from iTunes and such like.

It being near the start of the month, I felt a bit flush with money and went for a Dell Studio Hybrid machine. This could be described as a desktop based Laptop machine - it uses laptop (low energy) components in the desktop case. Maximum load it will draw 44w. It seems ideal under the auspices of this project too - when replacing anything, go for the low energy usage item, so long as it will do the job.

It's due to arrive on August 28 - after then, I guess I'm using about 150w less per hour of use. Okay, that'll mean 15 years to pay for it from energy saving alone (until the cost of electricity goes up). My old machine will cascade to my wife (but also now feature multiple logins, one for my son). Her old machine will be broken up and parts disposed of (some bits will be reused, others given away or sold on eBay).

It also gives us a space boost - the Dell Studio Hybrid is tiny and will sit on the desk, rather than to the side of it.