As a whiskey nerd with hundreds of bottles, it depends on what flavor profile you like. Someone mentioned trying one from each category to see what you like first and I think that's a good suggestion.
Here are some starters:
Islay: Lagavulin 16 or Laphroaig 10
Highland: highland park 15+
Campbelltown: springBank 10
Speyside: macallan 15+
Japanese: hibiki harmony, yamazaki or hakashu 12
Irish: green spot
Bourbon: Buffalo Trace, Weller, eh Taylor
Rye: willett 4yr
American: jack Daniels single barrel, high west
Taiwanese: kavalan
Sherry bombs: aberlour abunadh, tamdhu
Most on this list are cheaper bottles but once you define your favorite styles you can move up to nicer bottles