Re: +1 for X220 mention
My t61's have software that allows the battery to fall to about 95% before recharging each time. The family has four, and I have only bought two new batteries (I think they date from about 2008). Two are in constant use, and tow just get occasional use.
I also have a T21 which is still used as a dumb terminal for Sun servers, and a T43 with SSD which I use when travelling cos its smaller than a T61. Some have had CPU upgrades. All have max supported memory, and one runs windows - but has an SSD in where the DVD used to be and runs FreeBSD.
I will probably buy one of these new-fangled devices. It will probably run FreeBSD.