I'm typing this on a Thinpad T520, which I have had as my work machine
since the middle of 2012. It has spent almost its entire life on the
ship I serve on, and is still working perfectly. Dual-boots between Win7
and Linux Mint (currently 17.2). It is a pleasure to type on, and there
are only two things I would change:
1) the addition of USB3
2) addition of an NVidia graphics chipset
It has recently been upgraded with the addition of an MSATA module which
has just made it even better. If you see one of these, I would recommend it.