I am, and always will be, an apple guy. Apples may not be the most perfect choice, but a perfect apple gives a reasonable fertilizer (especially with all gardening challenges done) and since it's such a basic plant you could get huge amounts from every single harvesting. Some plants give just out so much more fruit above the more rare ones.
Let's see, life fruit, garlic and dragonfish are usually great, but from one of the plants you maybe get 2-4 max per harvest, and if you're growing dragonfish with the omniplant, about the same. To sustain a huge garden you would need whole plantations just to grow fertilizers! With good ol' apples on the other hand, you could sustain your whole backyard with just 2-3 trees with almost the same quality!!!
I never misses that opportunity.