OMG! You might just start a debate with hardcore Star Trek Fans... Trekkie vs Trekker... Some prefer one over the other. Me, I'm good whatever you call me. I'm a big fan, either way.
What's my favorite? If I'm trying to impress, I'd say Next Generation. They had a really good mix of serious and fun episodes, and I think Picard will always be the embodiment of Captain for me. Sorry, OG Kirk. Plus, it really is the best series in the franchise. But If I'm being honest, Voyager is my guilty pleasure. Sure, its sillier than most, but turning the Borg into the series' main villain gave Voyager some of its best episodes. They also had a good mix of funny and serious characters. The only thing I didn't like about the entire series is they never went back to their Unimatrix Zero storyline. I want to know what happened to all those self-aware Borgs. Honestly, though, DS9 and the original series were the only ones I didn't watch. DS9 cause the idea of them staying in the same place bored me, and the original series cause its hard to find episodes.
As for Picard coming back... I'm excited and anxious. I have a feeling the new Picard series will be more like Discovery than Next Generation, though. Patrick Stewart did say Picard might not be a captain anymore and he might not even be the same person as the one we last saw in Next Generation. So I have a feeling it will be darker in tone, like Discovery. We'll see.