My requirements include light weight and long battery life. Those don't necessarily go hand in hand as the bigger the battery, the heavier the machine.
Windows 10 and Google Chrome, and I guess to a fair extent even Apple, all now try to get you to put your data in their cloud. Whether you want to do that or not, it does cut way back on disk space requirements and worries about backups. Windows 10 really pushes it now. Google Chrome is designed about the cloud.
While there are some nice Chromebooks out there - especially the new Samsung Chromebook Pro - if you are looking for a Windows machine you might try this one
. This one has 8GB, 250GB SSD, 12 hour battery life and about 2.5 pounds an dthe power supply is really really light. It has an SD slot and a USB-C slot, so should be somewhat future proof. It has a micro HDMI port also. It was just on sale on Prime Day for $620, so if you shop around maybe someone has it cheaper than Amazon. It should get done most normal stuff. It's not going to be great to playing games or doing intensive computing, but for day to day stuff - it should be pretty decent. It should let you watch you porn collection on your flights to Europe without running out of juice.
Most Chromebooks will have 4GB of memory - which really isn't enough IMHO. 16 is much better, but it's very hard to find a system under $1000 which has 16GB, so you have to look around mostly at the 8GB machines.
Having a 250GB SSD is nice. More is always nicer, but with putting space clogging things like pictures and video in the cloud, it's probably not needed. Windows 10 takes 25-40GB. Office is "pre-installed" on the system - but I assume you have to pay for it and probably the pre-install is really a just an installer.
12 hour battery life is hard to beat. Not weighing a ton is also hard to beat.