As someone who grew up when Red and Blue came out, I must say I like the first two generations the best. However, the Pokemon designs appeal to me solely because of nostalgia, not creativity (although, they were more creative at the time than any competitors).
I was actually going to quit Pokemon after Silver, since I was satisfied with where the franchise was, and Gen. II was far superior in graphics and gameplay to Gen. I, while including the entire area of Kanto. However, I recieved a copy of Ruby as an unexpected gift and was immediately hooked by the creativity of the Pokemon. Despite my dislike of Treecko and Torchic which prompted me to pick Mudkip, I enjoyed the designs of nearly every new Pokemon. They were different, yes, but that was not a bad thing. It opened up my world of Pokemon because I realized that it didn't have to be exactly like earlier games to still be the same Pokemon experience I had come to enjoy. The beauty of the graphics and new environs just made it that much more appealing.
When Diamond and Pearl came out, I was much more unsure about the designs, but they have grown on me over the years because I gave them a chance. And as they have done so I notice more and more that they are still in almost the same style as earlier Pokemon, they do have that "Sugimori touch", and I just couldn't see it before. And from what I've seen of Gen. V, the designs are much better and much easier to recognize as Pokemon than Gen. IV was.
Now, I still have newer Pokemon I don't like the designs for (e.g. Nosepass, Hippopotas) but there were also older Pokemon that didn't grow on me until their newer graphics and movesets in Gen. III, such as Farfetch'd, Lickitung, Aipom, Igglybuff, etc. (well, I still don't like the look of Igglybuff).
So basically the point of my rambling wall of text is to give the new guys the benefit of the doubt and don't compare them to the earlier Pokemon until you have the chance to get used to them. Nostalgia vs novelty always skews the balance too much to render objective judgment now.