(this isn't as many as it looks - lots are listed in multiple places)
If you like coffee vapes, start with Coffee Espresso, Fresh Cream, and Tiramisu.
If you like fresh fruit flavors, you'll like most of FA's. The standouts for matching real fresh fruit flavor best, IMO: White Peach, Strawberry, Papaya, Blackcurrant... If you get any fruits at all, get Lemon Sicily, the flavor of limoncello liqueur and generally great for mixing with fruits.
If you like fruits sweet, pick up Custard, Fresh Cream, Marshmallow, Pear, and Meringue Nonna Cake. Consider Cardamom and Anise while you're at it!
If you like sweet-and-creamy flavors, Vienna Cream and Custard are two you'll need. If you like Bailey's, add Irish Cream to the list. Fresh Cream and Catalan Cream should already be in your cart, lol!
If you use vanilla for mixing or standalone, FA's three vanillas are essential (okay, I'll admit Vanilla Tahiti is less essential than Classic and Bourbon). Each has different uses. For a sweet-creamy bakery vanilla flavor, don't miss Nonna Cake!
If you like bakery flavors, you need Apple Pie (rich crust for mixing) and Cookie. Add Tiramisu only if you like coffee/chocolate, Vienna Cream for vanilla fans, and Joy for the pastry flavor (especially if you're willing to do more complex mixes)
If you want just one dark berry flavor, Forest Mix is the way to go. If you can get one more, Blackcurrant.
If you like nut flavors, Hazelnut or Nut Mix can't be beat for real nut flavor. But if you like nuts sweet, also get Marzipan.
If you like cocktails and alcohol, don't miss Brandy, (Irish) Whiskey, Gin, and Jamaican Rum.
If you like mints, Spearmint and Peppermint are exactly the flavors you expect them to be - no menthol surprises.
flavors only FA has and does a perfect job with: Torrone, Cardamom, Meringue (note 5/21/2015 recent batches have been subpar!), Marzipan, Mangosteen, Fresh Fig, Liquid Amber (to make fruits taste warmly fermented, like cider)
top flavors FA makes better than everyone else: Coffee Espresso, Fresh Cream, Cinnamon Ceylon, Cocoa, Coconut, Hazelnut, Licorice (for Aussie candy flavor), Black Tea, Tiramisu, Nonna Cake, Cola, Maple Syrup .. (this one could go on and one, but those are especially notable as the best IMO)
(I'll leave tobaccos to someone else)
Whatever you get, you'll be back for more!