Ask HN: What do you use to manage your TODOs?

I'm a Software Development Manager for a company that works across three locations. I have a small team here that I work with during the day, and then I interact with two other dev centres about 9 hours behind us. As such, I'm usually inundated with lots of things to check, follow up on, take action on and look at in the future. I've tried a few systems, most notably GTD, but have either found them too onerous or just lost steam while trying to do that and my actual work.

What are you using to track your work? What have you found to be a practical, low-overhead way to manage the influx of things you need to track and do?