CABLE's getting a bad label. Why? Soaring monthly fees and spotty service.It's too bad. During the years the networks dominated, television earned the title "The Timid Giant" because programs lacked substance and variety. Cable channels, today reaching 60 percent of American homes, have brightened the picture. While there's plenty of dross on cable, there's gold too. CNN's coverage of the Gulf war and C-Span's continuous eye on the workings of Congress are just two hints of cable's potential. But just as programming shows promise, some cable system operators are angering viewers, engaging in what is little less than bait-and-switch tactics. Many who signed up for service at a modest cost have found their local operator asking for hefty rate increases each year. Since each cable operator operates exclusively in a city, town, or region, the customer cannot chose another company. His only choice is no cable service at all. Recent steps by the Federal Communications Commission to permit local regulation of cable costs are timid. They cover only markets served by fewer than six broadcast stations (which excludes most major cities), about one-third of all US households. And, depending on how the operator defines "basic" service, the price of many popular channels - such as CNN, ESPN, MTV - may not be regulated at all. A House of Representatives telecommunications subcommittee is currently holding hearings on a bill with more regulatory bite. It would require operators to provide basic channels "at cost" to customers. A second tier of popular channels would be linked to the price charged by companies in comparable markets. Such regulation is a good idea - for the short term. Longer term, competition can work. Recently the US Supreme Court ruled that Niceville, Fla., could set up its own cable TV system to compete with Warner Cable Communications. And other technologies, such as microwave transmissions sent directly to small, inexpensive receivers in homes, may also provide alternatives. Then when viewers cry "I want my MTV," they'll finally have a choice as to who provides it - and at what cost.