My HH must-haves:
1)
Clutch wallet. It's hands down the best wallet I've ever used. I adore it. The only problem that I have with it is that the turnlock comes open in my purse, but I understand that they've fixed that on the new version -- so now it's perfect. (And it's only a minor quibble, anyway, since it's so far superior to other wallets that I've had in the past.)
2)
Carryalls. They're so simple, but they have made a world of difference. The inside of my purse used to resemble a garbage can. Now it's much more organized, I can find things quickly and easily, and -- wonder of wonders -- it's quick and easy to
switch purses, something I formerly did about once every three or four months because it was such a hassle.
Those are my only absolute everyone-in-the-world-must-have items. The rest of my list is subjective/according to taste.
3)
Corcovado. For use as a carryon/large schlepping bag. It looks much nicer and more polished than the old bookbag I'd pressed into service for the last umpteen million years.
4)
Havana. The shape of the bag, IMO, showcases the gorgeous buttery-soft leather to perfection. This is the bag that got me into Hayden-Harnett in the first place. It's a showstopper.
However, it really only sings to me in certain colors (Saddle, Yam, Cordovan, Anthracite, Oyster). Others leave me cold (black, gray, the famous VCP! They are lovely on other people, but wouldn't be "me."). Like I said -- totally up to individual taste

.
I have lots more HH that I own, use regularly, and love -- but if I were introducing a new person to HH and they asked me for "greatest hits" or "essentials," these are the items that I would point them towards.