14" laptop.....smaller the better for me for tuning.
For in-car (OBD2 stuff) and under-car (oscilloscope) I like the 10" (or so) netbooks (but I don't have my own yet, I'm undecided on which one).
15" laptop for datalogging & programming but wish I had a 10" HP mini
2008 2WD Ext.Cab Silverado 1500 6.0 V-MAX E38(L76) & T42(4L70E) MAF Only CL Corvette Servo AFE CAI INNOVATIVE LM-2 WBO2
FLASHSCAN V2 & AUTOCAL
I currently use my 17.3" HP for logging/tuning. I had a 10" netbook but it quite charging and it would cost as much to fix it as I paid for it. Picked up a 12 cell extra cap battery. It will last for about 7 hours of contunious use before it needs to be charged. And I have a hard wired 1200w power inverter under my rear seat.
2011 Cadillac Escalade ESV. BTR 218/224 .553/.553 110LSA. Built 6L80 with 278mm Circle D 2800 stall converter.