I've been finessing the way that I deal with tasks over the last few years, having tried GTD and found that it needed some tweaks. I think this is normal, any methodology might need changing to adapt to different people and roles. Specifically:
All work comes in via my email inbox, or verbally.
I manage a team, so sometimes I need to be aware of what they're working on.
I need to check for new email about once an hour in case of urgent emails (I can't just read it once a day).