One way I keep motivated is by having several bikes to ride, if I feel nostogic, I'll pull out the vintage Schwinn, if I want to get somewhere fast, I'll pull out the road bike, if I have some time to get to my destination, I'll pull out one of my hybrids, or my MTB with big knobby tires for that extra workout. If the weather is bad, I also have a foulweather bike, along with decent foulweather outerwear to match it.