Rearranging monitors without additional software is easy. The usual right click => resolution routine (Win7), click 1 or 2, tick it is main, done. I don't think it can be much faster without a keyboard shortcut, though you may prefer it in the system tray or something. You can also actually drag and drop the monitors there, switching them around and fixing the height at which the cursor will move to the other screen if they are not of the same height, when crossing the edge.
If you want a different wallpaper on each, just prepare an image the size of both your monitors combined. If your monitors do not use the same resolution, you will have to do some maths to position the smaller one in the right place (hint: check out the Resolution tab to figure out). The load it is your tiled wallpaper. Tile is the only one way to span across more than one monitor instead of replicating. Just figured out today.
BTW, even if you actually wanted to use the same wallpaper on two monitors working each in a different resolution, you might want to follow this method in order to provide the system with a properly resized image for the other monitor (not like Windows's own wallpaper scaling is bad).
Just bought a second monitor today, by the way. I had been using a borrowed one for a day or three but I used to have a laptop with an additional external monitor at work. That's how I learnt how great it was to work on two. Right now I'm translating repetitive texts and I can display additional two full-sized documents besides the source and target. Gives copy-pasting a whole new dimension and enables me to earn money faster, while preserving my sanity by sparing me the continuous awful ALT-TABbing that makes you dizzy after several hours of doing it.
The funny thing is my old monitor is a glossy (HP w2007v, very decent monitor, except it has a D-Sub VGA socket only, while w2207v has DVI) and my new one (LG W2361V-PF) is a matte. Using a dual-monitor wallpaper doesn't make much sense as things look quite different between the two.
If anybody is considering getting a second monitor, I would seriously recommend getting the exact same you have (so you buy two new ones or find a used twin at E-Bay for cheap) unless you have a good reason to do otherwise, e.g. you either can make them look the same or don't care/want to (or badly need Pivot--which comes with the additional bonus of a longer telescopic leg which means you don't need to use books like I do). (And anybody wishing to play old games on a new monitor: having a real vertical 1200 may help).
Eh, I already need a third! Need a fork cable bad.
