re: So I need to stock up my liquor cabinet from scratch...

Tonic and soda definitely expire and they don't have as long a life as I would like. I've thrown more out than I care to recall, so read the expiration dates when making the purchase. Same with cold drinks. They expire and they taste like crap, shortly, thereafter.

I'd recommend getting some vermouth, as well as the bitters. I keep, on hand, cherries, olives, lemons, limes, an orange, a bloody mary mix, marinated green beans and a few other things, on hand.