For me the definitive list is:-
1) A work bag that is not too big but still roomy enough for a small umbrella, wallet, company pass, keys and other randoms. Has to look stylish but business like, preferably in black leather (still looking for one so suggestions are appreciated!

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2) An oversized tote bag in tan leather - goes with everything. Mine is one I bought in HK on holiday, think it's a local brand but so fab
3) A biggish weekend/ daytime going out bag - Balenciaga City in Storm for me
4) A dressier going out bag - for me this is the Chanel jumbo classic flap in caviar or a trusty
Prada shoulder bag
5) A cute cross body bag for really casual occasions - I use the Marc by Marc Jacobs Petal to the Metal pochette in black
6) An evening clutch - I really love Alexander McQueen skull knuckle duster clutch, don't have one though
7) A carry-on-the-plane bag that can fit loads - mine is Herve Chapelier in camouflage print, matches everything!
8) A beach bag - I get a new one every summer. Or I just use the freebies from the mags lol!
So that's 3 more than 5 but all essential to me.
Bags that I would love to have are:-
1) Hermes birkin - this can go in category 4 above - dressier going out bag
2) A little Chanel bag for those "have to dress up but not that much" occasions, to supplement the evening clutch. But I don't want a WOC and don't like any of their pochettes at the mo so given I don't even know what I want, it's a bit hard trying to get this lol.