This will be my only machine.
My main usage will be development(visual studio, virtualbox, sql server), skype video, 1080p movie watching, browsing. I don't play 3d games.
I plan to run it 24x7.
Max weight 3.5lb. Core i5 or similar performance. Has to be silent or at least very quiet. I'm very sensitive to noise. Budget $1000 or less.