I typically carry around two notebooks on any given day. They are of very different character.
The larger (and significantly more expensive) of the two is my notebook computer. I use a Dell Vostro 2510 which I’ve just had a quick look for on Dell’s site. Apparently they no longer produce them which makes mine a little bit special. It’s red. It only ever came in red. I don’t think I know anybody else with a red computer so it is pretty neat. The guts of it are a 2.0 GHz dual core processor, 3 GB of RAM, 160 GB hard drive and an Nvidia 8400M GS 256 MB video card. It does rather a good job of running Team Fortress 2 and Battlefield 2 (the two games I’m into heavily right now). I was going to recommend it to other people but, as noted, Dell no longer sells it. I think they’ve probably just rolled it into the 1510 or 1520 line.
The other notebook is a more traditional sort of thing. It’s a Xonex rü notebook in chocolate brown. I picked up a three pack for the same price as a single Moleskine notebook of comparable size (though lacking the cachet of the Moley brand name). I got a square ruled (graph paper), standard lined and unlined, all in the same colour. The lined is being used as a fuel and maintenance log in the car and I just finished up using the square ruled book at the beginning of April. I am really liking the blank pages of the unlined book and I don’t imagine I will go back to ruled pages any time soon. I use it to keep to do lists, notes on sermons or things I hear on the radio and I’ve done a bit of drawing. I’m keeping a calendar in the back few pages as well. The rü books have a pocket in the back (where I kept my library card until fairly recently) and I’ve added a few things. I stapled in a piece of ribbon to use as a book mark and glued a small piece of sandpaper into the back cover that I can use to sharpen my sketching pencil (which is really a Staedtler drafting lead holder). I’ve also pasted a small calendar (apart from the one I’m keeping in the back pages, this one has just the dates with no space to write anything) in for quick/easy reference (especially when I want to know what day of the week somebody’s birthday will be).