I'm new to GTD, and am really noticing a lot of changes so far. Very excited.
Unfortunately, the problem I have, the continuously plaguing and frustrating trouble of the past 10 years is my inability to decide on and stick to any particular type of calendar.

I've tried:
Palm PDA
iPod
iCal
Daily Planners
Desk-blotters
Printed calendars from a software

They all "kind of" work. but now that I'm streamlining my workflow, I need to reevaluate what type of calendar will work best for me.
My weakness is gadgets, but I get the sense that these are distracting more than efficient.

Bottom line: what factors should I consider when choosing an effective calendar system? This requires more of an answer than "Pick what works for you" because I'm not sure what works, and trial and error in this matter is costly in time and resources.

Thanks for any help that can be tossed my way! I'm looking forward to being a productivity ninja like all of you!