Fourth gen through my friends when they were using pokesav. Eventually I started to learn how to do it legitimately without cheats during pearl with aid from serebii.net. Great website btw. First EV trained pokemon was Dragonite. I started to give a crap about IVs around late gen IV.
Recently Finished Game: Ni No Kuni (PS3), The Last Story (Wii) Current Game: Pandora's Tower (soon) (Wii), TBA (PS3), MH3U (WiiU)
I'm in pretty much the same boat as TC. Haven't played for 6 years when Diamond first came out. I had always known about EVs and IVs pretty early on, but because I had no way of seeing them, I didn't pay much attention. Now I'm replaying all the games and actually focusing on bringing out the real power of my Pokemon..... Can't decide if it's a good thing or a bad thing, considering I had always liked Pokemon for how easy and laid back it was. Now if I notice that a Pokemon is weak, I try to adjust its stats to help it to the point of tedium.
The mind of the subject will desperately struggle to create memories where none exist... ~~Just give me all the bacon and eggs you have~~