Hi! I don’t have a tablet but I really wish I did–I see people bring them to conference sessions, meetings, etc and they seem like a lighter, easier thing to travel with. Our dept appears split on having them or just bringing a regular laptop.
In terms of other tech that has made my life way easier: Zotero (citation manager, get the Word plug in and YOU WILL NEVER HAVE TO CITE BY HAND AGAIN) and Evernote (keeps all your notes in one app–I didn’t see the value at first but it’s far more searchable than going through all your word docs) have been my two favorite upgrades. Also, an hour tracker is a good way to keep yourself on track when you work (and to recognize that even when it feels like 60 hours of work a week it’s really not!).
Lastly, not grad school specific: I’ve been using Cladwell to get dressed every day. It’s $40 per year (sign up on their website, not the app store), and it just makes getting ready totally brainless, in the best way possible.