I honestly don't understand the hate towards Gen I. Pokemon fanbase is literally the only fanbase in the world that encourages you to hate the original games.
Firs of all: I'm not a genwunner. I just had to make this clear since someone would eventually start accusing me for genwunning. I've played Blue, Yellow, Gold, Sapphire, LeafGreen, HeartGold, Pearl, Platinum, Black and Black 2 and I think that gives me a good perspective of the series. I've been playing Pokemon games for about 12 years now and I still like all of them, every single one.
Usually people say that the old games suck because of the outdated graphics, mechanics and all the glitches. Of course older games may seem outdated but it doesn't really mean they suck. Gen I still even today offers a relatively long and enjoyable single player experience, especially if you take into account the limitations of Game Boy. Glitches are something that have been present in every generation (
http://bulbapedia.bulbagarden.net/wiki/List_of_glitches_in_Generation_V).
Although Playstation 3 is my main platform for gaming, I still play Playstation 1 games quite often. They too seem outdated when compared to PS3 games but it sure as hell doesn't mean they're bad games. Based on my experience, you just don't suddenly stop liking a certain game. I still like all the games that I liked 12 years ago and I like games that I liked 5 years ago. It's not about nostalgia, it's just about good games. I liked Gen I then and I like Gen I now. I've always been extremely confused about the attitude on /vp/ and the ever-present hate towards Gen I. Maybe I'm just weird.
Since you're probably wondering it, my two favorite Pokemon games are Platinum and Black 2 