I mainly walk everywhere I go, but try to fit in rollerblading and cycling whenever I can. None of them for exercise, just the fun and variety of the 'feel' of the 3 modes of motion. Cycling obviously covers the greatest distance, walking is the easiest, and rollerblading (to me) is the most fun and 'free' feeling for me, but it's the hardest to master if using it as an actual form of transportation (but doable if you're skilled enough and fearless enough to brave a busy urban area). Walking is my default mode, and when sightseeing, I usually opt to walk because it's low maintenance (no need to worry about locking up bike or switching rollerblades off my feet when going indoors).