FOR all the talk these days about synthesizers, digital samplers and all the other electronic musical marvels, it's still hard to top an electric guitar as the essential rock instrument. Even in Britain, where the pop market often seems hopelessly in thrall to novelty, the guitar remains the bottom line for most bands.

The Screaming Blue Messiahs, in fact, seem virtually all guitar. Sure, there's enough drum and bass behind this British power trio to give "Gun-Shy," the band's American debut, plenty of dancefloor punch. But it's Bill Carter's guitarwork that sets the tone and dominates the sound. Carter is basically a rhythm player, not a soloist, and he employs a big, beefy sound reminiscent of Belefegore or Killing Joke. But where the others rely on a stripped-down new wave approach to rhythm guitar, Carter has a taste for rock classics, sneaking country flourishes into "Twin Cadillac Valentine" and underscoring "Smash the Market Place" with stinging Bo Diddley licks.

Similarly, the Jazz Butcher makes his own pop allusions, but underplays them as well as his guitar sound. As his nom de rock would suggest, the Butcher's solos serve up soft, jazzy chords most of the time. And on "Bloody Nonsense," his second American album, they're perfectly appropriate to the "Walk on the Wild Side" groove of "The Human Jungle" or the Aztec Camera-style swing of "Partytime." But before assuming that the Butcher is some sort of sophisticate, check out the loopy lyrics to "The Devil Is My Friend" or "Death Dentist," where, in addition to being delightfully eccentric, the Butcher and his bandmates happily rock out. SCREAMING BLUE MESSIAHS -- "Gun-Shy" (Elektra 9 60488-1); JAZZ BUTCHER -- "Bloody Nonsense" (Big Time 10014-1); both appearing Friday at the 9:30 Club.