Here in Central Texas, any favorite plant has to be tough! My favorite annuals are zinnias--mostly because our bees love them. They need some supplemental watering, but with a little luck, they self-seed and we have two crops from one planting.
My favorite perennial is easy to answer--roses! I adore roses! When we first moved to Texas from upstate NY we were told "roses won't grow in Texas" and I seriously considered moving. However, roses DO grow in Texas--especially the antiques, own-root and Knockouts. Grafted hybrids are short-lived perennials for us. Texas climate and soil is a challenge, but shoot, if it were easy, it wouldn't be gardening!
Welcome to the forum, David, and don't be a stranger.