You have come to the right place for ideas! I won't focus on systems...mine is Nirvana. Honestly, it works so great for me I can't understand why everyone isn't using it. That being said, you need to find the system that works for YOU...not me.
It may be helpful to think of your time back to GTD as just an adventure. Explore, walk around, see what works for you and what doesn't' work. I stumbled on Nirvana once and didn't think it was helpful. Played around with Evernote, looked at many other system and then through a friends help looked at Nirvana again. The lights went on and all was clear.
So, play, investigate, don't get too attached. Each step will bring you closer.
iPad, iPhone, MacBook, PC; all running Nirvana, iCalendar and GMail
Mastering Workflow (2012 & 2013)