based on your flickr photos and your camera type, i'd say you don't really need a monopod. just proper handholding techniques will suffice since you take mostly daytime street, candid and flora. reasons being:
1. monopods are useful for support for really heavy setups (e.g. long lenses) where tripod is prohibited/not feasible. so unless u plan on shooting birds, racecars, fast sports with a 300, 400 or 500mm lens, monopod will only make your street/candid photography harder;
2. extra stabilization for night shots where simple handheld can not make it. and this is only for speeds 1/20s or 1/10s. if you're doing LE shots for 3-30 secs, better use your tripod instead;
3. monopod ballheads, IMO, are redundant. monopods are meant to take the weight of your camera so its best orientation is straight up, with the camera centered. others might argue its if you want to take in portrait orientation. but if you hang your camera to the side as in with a ballhead, you move the center of gravity to one side making it difficult to stabilize the monopod. these are just my opinions, of course, and others may disagree, but its a point to ponder if you REALLY need a monopod for now.