I almost always start with Alyce and 4 SPA's, then adjust the rest of my list according to strategy etc. The few times I haven't taken at least 4 SPA's to start with I really regretted it, plopping a DE right in your enemies face turn 1/2 can be a priceless ambush! And SPAs go down so easily that it can be hard to summon enough during a game.
If you've got the stones for it a necropunk and killjoy paired with a summoned DE can be hilarious. I once popped out KJ and a DE at the beginning of my second turn and proceeded to kill EVERYTHING except Sonnia.
I've been using Ryle a lot recently but to be honest he hasn't exactly wowed me, I just never ever seem to get his triggers off or the extra damage from his gun. He seems like one of those models you'd be wanting to hold a card or two for to get these abilities off but sadly, if you're playing Levi and not changing your hand every turn you're doing it wrong.
I've tried using a watcher and, while I can see the potential, especially with Leveticus, it's not really achieved much so far. Will work best against certain crews that rely on cover to screen their advance ('tina, Nico, stitched etc) or ranged crews that like to hang back and snipe (take THAT Nino! I hate that guy)
I had fun with a steamborg, but it still paled compared to the DE.
I've got a Teddy, but still never used it. Being on the whooping end of Teddy before though, I can see the appeal as he doesn't need any specific cards to kick serious ass.