Finlandia. Straight and cold.
I used Finlandia when I got into infused liquors in the 80's because they were promoting it.
Now, I have moved onto Tito's for that and do cucumber or watermelon. The cucumber is great with a Topo Chico on a hot day with a cigar. Also use Bombay Gin for cucumber gin with tonic, just delightful!
I do pineapple infused white rum to mix with Waterloo Coconut and it's like a healthy Pina Colada.
1800 Tequila infused with watermelon, mango, peaches or strawberries is also good for margarita's that are not too sweet but still carry the flavor.
If y'all haven't tried Baja Bob's Sugar Free mixers, I highly recommend them and have used every one of them. I was watching my sugar before but now, like a hawk, and they use Splenda and it's very good. The Marg, Triple Citrus Marg, Mojito, Mai Tai and their Sweet n Sour are very good. However, forget their ratios and experiment with your own.