Oh and btw; Road bikes for commuting are not too stretched out, as long as you have the saddle slightly lower and a short stem or riser stem. I also have a bad back, knees and am not flexible. I use a high-saddle position because I love riding fast, and so I can show off to my school friends (Im 14) Tip: Don't ski... This is why I have a bad back and terrible knees, so I can't ride a bike for too long at one time. Also, get a part-time job (I do chemist deliveries for an hour and a half every week) of cycling, and you'll notice that you will in fact be getting fitter, and more flexible. You will also respect your bike even more then usual, as if you ride too jard in traffic, as I have done, you may put a dint in your bike and someone's car (also as I have done). The Reid Osprey Flat Bar is a great bike, feels the same as the drop bar version, just more upright. Out of a Giant Seek 1 and Cannondale Bad Boy 9, I would say the Giant. And don't get a lefty fork. Never. Always have a fork covering both sides of your front wheel. Fixies are also good for commuting, as they are so simple. And because they are simple, they are often cheap, and durable steel frames are common, which means your bike won't snap on a washing line like with aluminium and carbon-fibre. Hope that one helped too!