Starting from scratch

I am intrigued with the challenge but I've got a couple questions first: Is there any major differences between red/blue and firered/leafgreen or gold/silver and heartgold/soulsilver? Or would it be easier to just get a DS and go with firered, heartgold, ruby, diamond, and black?

I really only need one from each generation so my third question is: Would it be better to play with one of the original two games for each generation or play say, Yellow, Crystal, Emerald, Platinum and whatever they make for Black/White when it comes out?

Edit 1: Formatting

Edit 2: I currently have none of the cartridges in my possession and would need to buy a system and the cartridges to play, or play on an emulator but I've always found those a little bit less fun.