What gin should I use for an authentic Negroni?

Any decent London Dry — Tanqueray, Beefeater, Bombay Sapphire, or Sipsmith all work. The bitter Campari and sweet vermouth dominate the drink; the gin is the structural spine, not the headline note.

The Negroni is one of the most gin-forgiving cocktails in the canon. Because Campari and sweet vermouth together carry so much flavor, the gin's job is to add backbone (juniper, alcohol, dryness) rather than to be tasted. Three working tiers: (1) Solid everyday Negronis: Tanqueray London Dry, Beefeater, Bombay Sapphire. None of these are wrong, all are widely available, all under $30. (2) Slightly elevated: Sipsmith London Dry, Tanqueray No. Ten, Hayman's Old Tom (sweeter, a 'softer' Negroni). (3) Experimental: Bombay Bramble (berry-forward, an unusual but interesting Negroni); Hendrick's (cucumber-rose, you'll either love it or find it weird in a Negroni). Stay away from Plymouth here unless you specifically want a softer drink; the bitter Campari can overwhelm Plymouth's gentle botanicals. The point: don't overpay for the gin in a Negroni. Save the special bottles for Martinis and Gin and Tonics, where the gin is the lead.