Macs
Most often
Early 2009 MacBookPro5,2 1,920 x 1,200 pixels, 17", Mavericks
Occasionally
2000/2001 PowerMac2,2 (iMac DV SE (Summer 2000), snow) Kubuntu 7.04, probably
2006 MacBook 1,1 1,280 x 800 pixels, 13", Snow Leopard.
I used the 2000 Mac for a couple of days a fortnight ago, after I forgot to put the power supply for the 2009 Mac in the rucksack.
I used the 2006 Mac this weekend to tell whether I'll be happy with
a new mid-2012 MacBookPro9,2 with the same pixel density.