The first I played was Red, first I owned was Gold and Silver. As for starters, it's probably 40-40-10, fire-water-grass, for me. Rarely picked the grass types.
I only ever played the originals first because my sister's friend would bring her Gameboy over when she visited. (she lived a couple hundred km away) I would wait for it to be unguarded, take it, start a new game, play until she had to go, and then save over her file. This happened about 6 times, and every time she came back she would have a new complete/near complete file. Thinking back on it, I can only imagine how annoying that must have been.
My favourite Gen would have to be 3rd gen though, and was a little surprised to hear no one else I knew liked it. I didn't actually get into the 3rd generation until a year after it came out, I was at a pawn shop I check out every once in a while, saw Pokemon Sapphire, which I didn't even know existed. While I was there I picked up a copy of Red, Blue, and Yellow, because they were cheap, and have played through those more times than any others. For some reason my favourite parts of the originals are the parts I've played 15 times over, from the beginning to around the 3rd Gym, I guess nostalgia.
Red for me. Unfortunately, the game got fried when I was playing on a 40C (~110F) day in my friend's attic. I had 148 pokemon at that point. Needless to say, I cried like a little girl. Fortunately, I also had Blue version, and had traded over my event Mew, so I got my 151 in the end.
I've had at least one game from every gen since (R,Y,B,G,C,Ru,E,LG,P,HG,B1), and am soon to jump on B2/W2 as soon as it comes out over here in Australia.