Ooh, crikey! I don't think I've had as many as you lot, despite virtually living on my bike as a kid, and spending most of my adult life riding regularly.
I can remember:
1) A single-speed kid's bike. I remember my mum painted it ready to sell the day before I would have taken my Cycling Proficiency Test at school. I was the only kid who didn't get to take the test.
2) I know I had a generic kid's bike some years after that because I can remember a particular 20 mile round trip I did on it. I can't recall any details of the bike, not even the colour.
3) The first bike I remember in detail was a Raleigh Hercules Balmoral: an ugly, heavy, "council green" SA 3 speed "granny bike" with steel rims, cottered cranks, and sit up and beg handlebars. It was a Christmas present at a time when every other kid had either a Raleigh Chopper or a "5 speed racer". (Any bike with dropped handlebars was a "racer".) I hated that bike, but did many miles on it.
4) The first bike I remember buying with my own money was a second hand Peugeot "10 speed racer" second hand from an older youth. He was taller than me, the bike was far too big for me, and I paid over the odds, but I had always wanted a Peugeot. I liked the paint job/graphics. I put wide "cow horn" handlebars on it. I can't remember what happened to it, but chances are it was stolen.
5) The first one I bought brand new (on finance!) at the age of 18 was the cheapest bike in the shop: I needed transport. It was a Viking (or possibly a Viscount) 5 speed racer in a blueish purply colour, again with chromed steel wheels, cottered cranks, and a frame made of mild steel. I did many miles on that bike, commuted, camped, everything. This was the bike I did my first tour on, riding along main roads from Nottingham to Norfolk, then exploring childhood haunts, and sleeping in one of those orange plastic survival bags at the roadside. I also did a ride from Bury St Edmunds to Nottingham along the main roads including the A1: one of Britain's busiest roads. I also did my longest "day" on it: a 24 hour sponsored ride, mainly unaccompanied, in which I covered around 200 miles.
6) My first decent bike was a King of Mercian, Reynold's 531 double butted frame which I bought second hand through a Cyclists Touring Club contact. I built it up to my own spec with alloy wheels (luxury!) and 12 speeds (2 x 6 in modern parlance) and used it for commuting, tours, camping, and club rides. It was my first bike with "cotterless" (square taper) cranks and get this detachable chain rings. Years later, newly divorced, with nowhere to store it, and suffering from depression, I just threw it away, which I still regret.
7) 8) Around the same time as I bought the Mercian, my first wife and I bought a brand new Dawes tandem. It was a lovely bike on paper, but a new model with teething problems and we eventually had to send it back for a refund, then bought a Claud Butler tandem which was much better. We sometimes commuted on that, as well as touring, doing club rides (CTC and Tandem Club) and attending Tandem Club rallies.
9) A little later, I bought a second hand home built recumbent bike made of the back half of a standard bicycle and the front half of a small-wheeler. It was inefficient, uncomfortable, but strangely fun. I commuted on it a few times. I once got stopped by the police (blue lights, blip of the siren, everything) late at night: I was doing nothing wrong but the copper was a cyclist and wanted a closer look at it.
10) A few years after getting rid of the Mercian, I bought a modern sit-up and beg bike with 4 speed hub gears and alloy wheels. It was not a bad bike, but I never really took to it. I was unicycling more than I was bicycling.
11) The next was the Pearson Touchι, which is still my first choice for leisure rides and commuting. I bought it a year or so before fixed gear became trendy so it is a bit "staid" in design and colour: a charcoal-ish frame, close tyre clearances and dropped bars. If I had my choice again, I'd choose differently, but I have learned to love it.
12) I also have a 2 x 10 Giant Anyroad which is the most expensive brand new single seat bike I've ever bought. It's a good bike, robust, but heavy and over engineered for most of what I'm likely to ride it on.
Apart from that I've owned:
3 x 20 inch unicycles no longer own this size
2 x 24 inch unicycles now own 1
1 x 26 inch unicycle no longer own this size
2 x 700c unicycles I own one, with a custom-built wheel.
1 x 29 inch unicycle still owned
3 x 36 inch unicycles still own one. It is the size I ride most often.
2 x 24 inch ultimate wheels one broke. The second one gets ridden a few times a year.