If you work from home, or even if your employer provides you with a notebook, it might be tempting to start working from your desktop machine. Usually you benefit from more performance, a comfy chair, customisation through hotkeys and shortcuts and all the other perks the come from tailoring your home PC into the most productive device it can be. If you do get taken by this desire, I would urge you to resist it.
When I started as Weekend Editor, working across Gizmodo, Kotaku and Lifehacker, I set myself up on my desktop machine. However, I found it difficulty to disconnect from my editing work and switch gears to software development, which I do from home during the week. There was no natural cut-off point -- I just closed my browser windows and web mail, and then fired up Visual Studio. Instead of a clean transition from one type of work to the another, there was just this muddled process of closing and opening programs.
I've found it a lot easier to concentrate and shift into "developer mode" by keeping all my dev work on my desktop and my editing gear on my notebook. It also means I can completely customise my notebook for the sole purpose of writing for the sites. When I'm done, I just close my notebook, go upstairs and jump on my desktop -- perhaps stopping for a drink or a snack to reset my thought processes.
This applies to work and hobbies, too. Of course, not everyone has the luxury of owning a desktop and a notebook, so if you've found a way to make a clean break between projects, or entirely different fields of work, be sure to let us know.