I started with Red AND Yellow, personally.
I played Yellow more though, the battery died on it unfortunately, and Red I eventually did beat (I think...), I got blue eventually after I got Gold, but I lost Blue shortly after popping it in for the first time. I loved Gold, and eventually like all things I love I lost it too. Red and Yellow were given away by me at some point, not sure why.
I didn't get back into it until a friend gave me his copy of Emerald, and then after that I really got back into it with SoulSilver, skipping over the Sinnoh games entirely (Not my intention, but [parasitic bomb] happens.), and now since I just beat Black (Using the power of "[tornado fang] it, I'm using Action Replay") I'm going to get into Black 2.
Game Sync is a [tornado fang]ing piece of [parasitic bomb] though, I haven't used it in ages and its "Out of Energy".