Most of my favourites come from Gen 3. Gen 1 and 2 are my nostalgia fix. However, I recognize them all because regardless of the stubborn people they are all here and are all a part of the game. Same with anything that comes out with stuff people don't like, really. The SW prequels are still Star Wars, Robin is an important part of the Batman series, etc. They are a part of their universe and lying about it doesn't make it any more pure, it just shuts you off from something you may enjoy even if just a teeny tiny piece.
Back to Pokemon however, there are 649 of the things now, and while they come out in chunks it is hard to categorize them as such when saying what you like and don't like. There are pokes from all gens I don't care for, and ones from each gen I like a lot.
EDIT:
As for them running out of ideas, that is a statement I can't really get behind. Sure you've got similar things like two weakling fish that evolves into power and beauty respectively, or a worm that evolves into two similar looking cocoons because those splitting into a butterfly or a moth. And a lot of gen 5 things are almost direct counterparts to old guys, sure. But they aren't the same, and they are a lot different than a lot of other games would even try to do. I mean, I love my Final Fantasy, but in many of those games you're not going through two dungeons without running into direct pallet swaps. Not different attacks, stats (save for higher level) or strategies. And that's fine, it works there. Hell look at a book of real world animals and tell me that you don't start seeing things that are basics copies or super similar. The biggest problem I think is that Gamefreak isn't changing up really how/where you find your little rat guy or your bird friend, which is more of a problem with pacing design than monster creation.
It is perfectly fine to like old Pokemon over the new guys, don't get me wrong here. I don't think it is right to really hate anything though. No need to hate the new ones for being new, or for being (possibly) better, or out of fear that no one will remember your old buddy with the new shiny toys to play with. It's Pokemon, all of them are around and all of them have memories for someone, somewhere. None of them are going anywhere.