I liked all of them! But my first Pokemon ever was Chikorita, so I have a soft spot for that one. It started off my tradition of only picking Grass-types. In a sense, it seems to be the more underappreciated one because people typically prefer Cyndaquil and Totodile. Honestly, the reason I chose it was because I wanted an Arcanine and didn't want to have two Fire-types on my team. Otherwise, I would've gone for Cyndaquil. As for Totodile, I'm not really a big fan of Water-types, so I rarely choose that starter.
Of course, I was playing Silver version and had nobody to trade with... so no Arcanine. ;~; Still, I kept going on with the tradition. It all started with this pretty flower dinosaur. It seems like it'd be the one I'd have other than Cyndaquil as well, due to being very passive and smelling nice. Also, I love flowers. :3
But Quilava is still one of my favorite middle evolutions regardless. I've used all three because I've played these games from front to back more times than sane people have, so I know these starters pretty well. Typhlosion was always cool to use and I like how they have an unusual blue in their design as opposed to typical Fire-type colors. Very unique. As well, their shinies are pretty. :3