on a 5-mile commute to work i wear my office trousers and shirt, no problem with that. for all casual riding (to the shops, visiting friends etc) i don't wear cycle specific clothing or shoes. i like the comfort of brooks saddle (although i don't like their looks) and i can ride in jeans with no major discomfort up to 200km. lycra however is very good for fast riding, it doesn't flap about and tight layers keep you warmer and take less space in your luggage/pockets.