The Best Bag for Me? (A LV Newbie)

i say tivoli only because i do not like the popincourt at all. maybe a batignolles vertical like spacytracy suggested, but if you like the popincourt that much, go for it!
 
I say get the Tivoli! I love big bags even when I never carry that much because I can always throw extra stuff in on an off day. Plus, you've been obsessing over it for the last few months so go for it!!
 
It sounds like the PH would fit your needs. But, I think you should go with the Tivoli. You have to go with your heart and it certainly sounds like you love the Tivoli. You can get it and if you find it to be too large there is always the option of returning it and picking up your PH. Or as you mentioned you can get the Tivoli GM now and snag the PH at a later date.

Best of luck - both are fabulous bags.
 
Honestly, if you really have been eyeing the Tivoli for a while - go to the nearest LV and check it out - that may be the only way you will be able to decide. If it's not right for you I'm sure one of the SA's would be able to suggest something more your style. (That's what I've done a few times.) Sometimes when you actually get your hands on a specific bag you've been drooling over you realize it just might not work out for your own needs. Good Luck! And let us know what you decide...