In order , I had a short riding career ( stopped due to age/lack of coordination and valuing my life rather than a lifestyle/hobby/mode of transportation, I suppose I wasn't a "true biker" )
2004 Kawasaki ZZR250 - fun first bike except the carbs were terrible in cold/damp/wet conditions (early spring or late fall)
2007 Honda CBR125R - yes I downsized for my 2nd bike. Traded the ZZR in on this. Loved this bike. Fuel injected, no cold blooded nature in cold/damp/wet. Fuel economy was outstanding. So light and "flickable". Maintenance was so simple, valve adjustments and oil changes really were "dirt simple".
2008 Suzuki S40 - owned this at the same time as the CBR125R. Loved the simplicity of the big thumper. My lower back could not take the riding position and had to trade it in as I was sore after every single ride.
2009 WR250R - traded the S40 in on this & sold the CBR125R privately. Wonderful commuter bike, tall upright see-forever sitting position. Decent economy and poke. Bought the supermoto tires so had a true "dual sport". When it was time to go I sold it private sale as it was easier to get the value back with the SM wheels included rather than trade-in at a dealer.
2012 Zero XU - decided to try an electric motorcycle. The experience did not go well, it was broken half the time I owned it with one recall after the other that stopped it from working (BMS conformance layer coating issues, motor issues etc.). When it did function as it was designed to I really enjoyed it; no maintenance, no going to petrol stations, charge at home. The "electrons per mile" was outstanding too, about 0.53 Le/100KM. Sold it privately to an individual who didn't mind that the bike didn't work. Shame it didn't work more than 50% of the time...
2014 KTM Duke 690 - the last bike I owned. Mental is a good description. Tame at low throttle, fun if you got into it. Way more bike than I could handle LOL. Maintenance with two oil filters (the engine was originally designed with separate sumps for the engine/transmission) and an under-mounted exhaust system was not a lotta fun (yes, I am lazy).