I've been using a reusable 36oz/1L plastic "flip lid" bottle from Bezos's market - this is my third one (sadly replaced almost on a yearly basis) since I keep accidentally breaking the lids.
It practically comes everywhere with me - walking, cycling, in my backpack. This lid is starting to crack at the hinge and the latch though, but don't really want to replace it with the same thing again.
How long have you had you had your current bottle, and how are you finding it so far?
Insulated Klean Kanteen. It's got about nine years worth of debts and scratches.
I'd like the bigger capacity I could get from a non-insulated bottle — as I really don't need the insulation anyways — but I have become sentimental towards this old thing.