IF you haven't checked out the local entertainment scene lately, you're due for an upbeat surprise. There's some serious listening, not to mention dancing, going on out there.D.C. is rapidly emerging as one of the hottest music towns in the country.

In the past five years, Washington's reputation has gone from sleepy to lucrative as a record and concert market. Fact is, Washington can compare to any city - including the Big Apple - in the number of local bands, clubs and pubs drawing nightly crowds.

The scene bustles with all types of music. You can be mellow in Georgetown swaying to original folk tunes, or be outraged by "new wave" acts on F Street. There's tequila night at Rocky's, ladies' night at Louie's . . . there are, in fact, more stages and audiences than there are top-notch acts.

While local club managers are in stiff competition for name performers, unknowns are slugging it out to get on D.C. stages. Country- and folk-oriented Childe Harold is overwhelmed by offers from small record labels plugging new acts, says management. The problem is that many of the bigger groups are committed elsewhere in town. "The city is locked up," says a local booking manager. Translated, that means some acts will play only the Cellar Door, where record companies traditionally give their artists the big push.

What's it like to be the local nightclub kingpin? Cellar Door co-owner Sam L'Hommedieu acknowledges that after years of experience, his club is considered the place to play in The Nation's Capital. "Why should an act present itself in any but the most favorable light?" he asks rhetorically. Still, he adds, "Anybody can get any act they want, if they can pay for it."

Cellar Door Productions has helped Washington toward a flashier music image in the seven years since it ran its first concert (Gordon Lightfoot at Constitution Hall). And now the front-runner claims it's feeling increased competition for talent as part of the market's turnaround.

An array of new music showcases has sprouted in and around the District. Most offer a range of music styles plus special deals like half-price nights and 25-cent beer blasts; Louie's Rock City in Bailey's Crossroads features a ballroom-size dance floor and seating for 700 on three levels. Rocky Racoon's Saloon serves up its own brand of Tex-Mex food and country-western border music. At Desperado's, a raunchy '60s bar on the outskirts of Georgetown, a 10-month round-robin of open-stage competition, narrowed down to four acts from more than 300 entries, will wind up May 22 when one of the four - Jim Landry, Coyote, Stars & Bars and Ambush Pass - will win the $1,000 prize. The next round-robin is scheduled to start in June. Singer's Studio in Georgetown likewise gives struggling artists the chance to make it big - at least before small but generally sympathetic audiences.

For those keeping score, the newest arrival on the club scene is Greenwood's County Line, a bluegrass/country showcase on U.S. 50 in Arlington. It shares Des perado's staff and offers a similar open stage every Wednesday night.

Jazz, of course, has broadened its once-limited appeal, and Washington now boasts a wealth of clubs - everything from traditional rhythm'n'blues sounds to jazz fusion styles - for hardcore as well as casual fans. Renee Laude-Gravatt, disc jockey at jazz station WPFW (FM), claims there has been a "resurgence of jam sessions here." Jazz musicians have long since quit the underground and moved to upstairs lofts to play before paying audiences.

Blues Alley remains the major haunt drawing top jazz headliners. Pete Lambrose's Showboat Lounge in Silver Spring closed recently under the pressure of increased talent costs and heavy competition from other clubs. But among the dozen or so jazz rooms still going strong are Pigfoot, Top O'Foolery, D.C. Space (a relatively new, loft-style club) and Harold's Rogue & Jar.

On other fronts, punk rock did a fast fade recently (fortunately, some say). The Silver Spring club publicized as a major punk outlet never materialized. Although you can still find an occasional "new wave" group at Louie's Rock City and The Atlantis, a new downtown nightery, D.C. is certainly no London.

But the music business is high on Washington for reasons other than punk. For one thing, D.C. has a long history of promoting "black product" - trade jargon for albums produced largely by and for black audiences. Another quirk of the market: Bluegrass and blues, low on the commercial scale of importance, are especially strong here. Surprisingly, even country and western (variously labeled progressive or outlaw) has made major inroads in this white marble outpost.

Certain artists are pets of the town. Little Feat, Van Morrison, Emmylou Harris (for years a regular voice at area watering holes), Bonnie Raitt and, more recently, the Catfish Hodge Band have particularly loyal followings.

And suddenly several local groups are about to make a splash nationally after being nurtured by D.C. audiences. The city's had its homegrown superstars, like Marvin Gaye and Roberta Flack; now the almost-stars include the Nighthawks, Razz, Root Boy Slim, Starland Vocal Band and Rosslyn Mountain Boys.

As if D.C. needed New York's approval, Manhattan talent and booking agents do back up local claims to fame. "Washington is one of the most important towns to play on any club tour," according to Steve Levine, who handles national club engagements for the William Morris Agency. "It's a very happening market," a booking agent for International Creative Management concurs.

Perhaps the Capital Centre deserves thanks for putting D.C. on the concert-tour map. It's among the top concert grossers in the country - roughly $7 million annually - and a must stop for major tours. The small listening rooms have obviously benefited from Cap Centre spillover.

In any case, all the music mavens agree that Washington is at last near the top of the list of prime music cities. They say it's no longer necessarily more important to play New York; D.C. is just as vital.

No one is sure just when it happened, but somewhere along the line, the town made it into the big leagues of the music biz.

Consider the number of clubs coming alive nightly with rock, folk, country, jazz, blues, bluegrass and even punk sounds. Not counting bars with live entertainment (like the Irish pubs, Gallagher's and Four Provinces, or the several Mr. Henry's), the list of strictly defined music-listening rooms is a long one. A sampling according to musical style: