TNG will always be my favorite Trek. It inspired me to become an aerospace engineer. I really enjoyed the "anything is possible" technology, and the hopeful tone of the show. Data (and Spot) was my favorite character, and being a teen I did have a crush on Wesley Crusher (no pun intended).
Rewatching as an adult, I appreciate the episodes even more. I want to pick up the blu-ray sets, once we get us a blu-ray player.