Titanium Bar

Armor before weapons. The titanium set throws up a ring of shards whenever you connect with something, and those shards absorb hits outright, which matters more heading into the mechanical bosses than a few extra points of damage would. Its counterpart, the Adamantite Bar, pays out in offense instead, so the ore your world rolled changes how the tier feels rather than how strong it is.

After the set, the drill or pickaxe is the real priority, because it is the gate to Chlorophyte Ore and everything built on it. Make it early and the mid game stops feeling gated.

Do not dump the leftovers into furniture. Frost and forbidden armor both arrive later and both want more of these bars, and by then you will not want to go back for another mining run.