Personally, I love the IPad for exactly the reasons you mentioned. I use it for killing time, especially when vegging out on the couch, and it serves that purpose extremely well. I was considering buying a laptop for myself so I could leave my old one at home for the girlfriend to use, but the only functionality she really needed was the few topics you mentioned, and an IPad fit the bill perfectly. Although it was fairly expensive, I love that it is instantly on and extremely portable (brings a completely new world of bathroom literature haha). I know with SSD's you can get pretty fast boot speeds and ultrabooks are the new fad, but for minor computing like email, facebook, and surfing, I think tablets are pretty hard to beat. Look into them, you can certainly find tablets that will serve your purpose well for much less than a newly released IPad, and I also believe there are wireless external hard drives that can act as additional storage space for your tablet device, resulting on savings on the storage (unless you require a lot of onboard storage for travel). Also, I believe sometime this year Office for iOS is coming out if you require that functionality.
*Edit* Her one complaint is that there is certain facebook functionality that is not available through the iOS Facebook app, so she has to use the browser version, but I believe they may have quite recently released an update that addresses this, maybe someone else can confirm. *Edit*