Cats are self-cleaning, so unless they get into something (grease, skunk), they don't need a bath. I LOVE the smell of cat fur. Just stick your nose behind their neck and take a big wiff! Just a nice, warm fur smell. The only places they smell bad at times is their breath (some people brush their teeth...I'm too lazy) and their back end (if they just went to the pan or have gas..which many cats at the local shelter have because the food they get is not the best).
I've lived with 9 cats in my lifetime, and over that period, I've only given about 6 baths (for fleas, cat who got into oil!, and cat who just came off the streets and of unknown past).
The only other reasons for bathing a cat would be to get rid of fleas (especially on kittens) and people who are allergic, but you only need to take a damp washcloth to wipe them down and not give them a bath/shower.
What IS helpful to them is regular brushing, which can keep them from injesting too much fur and throwing up hair balls (which look more like tubes than balls to me). I found some great scalp massage brushes (for people!) in the hair care department of my local Walgreens. The cats at the shelter where I volunteer (and my own cats) LOVE these because they aren't harsh like some wire-bristle brushes can be.