I highly recommend "Dark Room". It may not have as many features (i.e. it's basically notepad in black bg/green text.) I think it'd definitely be easier on the eyes, though.
I actually used to use Dark Room previously, but it didn't play quite so nicely with some graphics settings and lack of a spell checker was a deal breaker. I write mainly fantasy, so it's important to me that all those strange names and terms are spelt consistently.
That Writer is nice. I like the portability and cross-platform support. The ability to log in from anywhere makes it so portable. I kind of worry about storing everything online and what they might do with it, but then I do use Dropbox to store to the cloud myself (archive to two separate hdds).
If you wanted to make Writer really full screen you can set your Task bar to minimised or set auto-hide (Windows XP). It will still be visible, but only as a thin line at the bottom.
Good find!
Dark Room is a good way to isolate yourself.
Their website. The page seems to be empty, though. I was on it a couple of weeks ago so it must be a bug.
Unless you're rocking a Chromebook and have no other options, I'd go with Google Drive or Dropbox, + Something like http://they.misled.us/dark-room or http://www.hogbaysoftware.com/product/writeroom
If your problem is that you are at various computers and you need something always accessible, then Scratchpad, or https://simple-note.appspot.com/ is a better bet. Simplenote has a pretty clean interface, although not inverted like WriteRoom etc.
It seems like these posts come up every few weeks, but I can't recommend enough fellow redditor craigerator's Smarter Writer, and for a bare bones word processor, Dark Room.
If you want fewer distractions try Darkroom for Windows. It's a clone of a mac program, but I use it for my short stories. It outputs into a text file, which you can copy and paste into a better editor after you have actually written something.
I like it for my writing, and I don't have to worry about all the crap I would play with in Word (or the damn grammar/spelling scribbles). Plus, outputting it into simple text makes it easier to copy/paste the end result into whatever you need without having to worry about special characters from other editors mucking everything up (I'm looking at you smart quotes).