I'm so 200% in agreement with you on the bike front. Since I was about 19, I've been riding my bike pretty much everywhere. I have actually never applied for a driving license, let alone owned a car, so it has just always been my way of getting around. I'm now 24 and it's really become a way of life for me. I don't even think about it. I started riding to work (about 45mins each way) when I was 19, as it was the most direct way to get there without a car. 5yrs later my weight is still sitting steadily around the 60kg (132lbs) mark, and despite the fact that I have pretty crazy yo-yo eating habits, my weight only ever fluctuates by about 2-3kg either side. And I'm 5'10", so that's a pretty ideal weight. Cycling has been great for my circulation & cardiovascular health, too.
My man & I are both avid riders & our relationship has only strengthened our enthusiasm for it. He now commutes on the bike also, and I have developed a passion for mountain biking. In fact, we're flying to Kuala Lumpur in August 2011 to spend 6 months cycling throughout South East Asia.