First, 1-51:
(WARNING: Controversial opinions ahead!)
Bulbasaur/Ivysaur/Venusaur Bulbasaur and Ivysaur have creative designs not based on any particular animal, don't have any flaws in terms of appearance, and are pretty cute, so I give them a thumbs up. Vensaur on the other hand is really ugly to me, the face is just really unappealing, so I give that one a thumbs down.
Charmander/Charmeleon/Charizard: Charmander and Charmeleon's designs are good. While they are clearly based on lizards they have enough that separates them, and Charmander looks very cute while Charmeleon looks very cool. Thumbs up for them. On the other hand, Charizard is SUPER-lazy, being just an orange dragon, so I have to give it a thumbs down.
Squirtle/Wartortle/Blastoise: Not a fan on any of the three designs. Squirtle is just a blue turtle, though it's pretty cute, Wartortle is just a turtle with wings, and Blastoise is just a turtle with a cannon on top. Not really much effort put into these, and they aren't aesthetically pleasing to me either, so thumbs down for all three.
Caterpie/Metapod/Butterfree: Again, none of them are creative at all. Caterpie is just a caterpillar, Metapod a caterpillar in a coccoon, and Butterfree is just a butterfly. And apart from Caterpie, who's pretty cute, none of them are particularly appealing to me, so thumbs down for all three.
Weedle/Kakuna/Beedrill: Once again, very little imagination put into them. Weedle's just a centipede, Kakuna a coccoon, and Beedrill a mechanical bee. thumbs down for Weedle and Kakuna, but since Beedrill's pretty cool looking and a mechanical bee is pretty awesome, thumbs up for it.
Pidgey/Pidgeotto/Pidgeot: Some of the weakest. All three are just birds, with almost nothing appealing about them, and don't really change much through the line, AND they don't really have much details that stick out to me, except Pidgeot's cool haircut. Thumbs down.
Rattata/Raticate: More of the same, Rattata's just a purple rat and Raticate's just a bigger fatter rat, it's also pretty ugly. thumbs down.
Spearow/Fearow: Spearow's another lazy bird Pokemon with no design details I like, thumbs down. Fearow, however, looks really cool, even if it is sorta lazy, so i give it a thumbs up.
Ekans/Arbok: Both are just snakes. Laziness abounds, even down to the names. Thumbs down.
Pikachu/Raichu: A CHANGE of pace. Pikachu and Raichu are my favorite Pokemon ever. Pikachu is like they had a checklist of what makes something cute, and it succeeded brilliantly. Long floppy ears, big round eyes, chubby small body, bright yellow fur, warm smile... I could go on, and Raichu is still almost as adorable. BIG thumbs up for both.
Sandshrew/Sandslash: Two more good designs. Both don't look TOO much like a certain animal, and both have pleasing designs, Sandshrew's super cute and Sandslash looks pretty cool. So thumbs up for both.
Nidoran/Nidorina/Nidoqueen: Good designs here as well. Effort put into them, not just an animal with tweaks, and look pretty cool as well. Thumbs up for all three.
Nidoran/Nidorino/Nidoking: More of the same story with these three, effort and coolness both abound. So thumbs up again.
Clefairy/Clefable: Not really a fan. Both are just Kirby, except less cute-looking, unlike a certain other Pokemon i'll get to real soon. Thumbs down.
Vulpix/Ninetales: Also, weak for me. Both have little effort put into them, just foxes with more tails. They also aren't particularly cute, either. Vulpix could be cuter but I don't like the way it's eyes look and the tuft of hair on it's head looks weird. thumbs down for both.
Jigglypuff/Wigglytuff: KYOOT! Sure, they may look just like Kirby, but with their big round eyes and adorable smiles, they just ooze cuteness, and I love it. thumbs up.
Zubat/Golbat: Both are just bats with little effort, Zubat is also really ugly with it's lack of eyes. Golbat is a bit better, but still not pleasing. Thumbs down for both.
Oddish/Gloom/Vileplume: All three of them are based on plants, but not overwhelmingly so. Oddish is super cute (just look at that smile) in addition to this, so I give it a thumbs up. Gloom on the other hand is really ugly, with it's closed eyes and constant drooling, so a thumbs down for it, but Vileplume swings the pendulum back to cute, so a big thumbs up there.
Paras/Parasect: Both weak. Both are just crabs with nothing that really stands out for me design wise. thumbs down.
Venonat/Venomoth: Venonat is one of my least fav Gen 1 Pokemon, a big hairy ugly bug pokemon, major thumbs down for that one. Venomoth looks better, but still lacks effort and is just a moth. So thumbs down again.
Diglett/Dugtrio: We finish off with two more weak ones. Diglett is just a bump with a face, while Dugtrio is just THREE bumps with a face. Also, what's underneath Diglett? I guess the world may never know. thumbs down.
