Of all the '70s bands that aspired to the heavy metal dais of Led Zeppelin, few came as close as the quintet Aerosmith.

They were brash, yes. They were crude. And they made one heck of a racket on stage. But, in the true Zeppelin tradition, they had something more: style.When most other bands stayed the course, afraid to tarry too far from the standard routes, Aerosmith ventured far off the beaten path with risky forays into blues and '50-style rock 'n' roll.

That brilliant potential was evident Wednesday as a rejuvenated Aerosmith took the stage for a solid two hours of music that tracked methodically through their 15-year career.

But it was clear, to this critic at least, that despite the commercial success of their new album, "Permanent Vacation," Aerosmith was never better than they were in 1977 - the year the band released "Rocks," a dynamite follow up to their previous hit album, "Toys In The Attic." Even though "Permanent Vacation" marks the band's comeback from the doldrums of such clinkers as "Draw The Line" and "Life in the Ruts," they still fall far short of the band they promised to be 10 years ago.

What happened? Well, drugs and wild living are the stuff of the Aero-smith legend, and that may well be what slammed the brakes on their careers. After the "Rocks" tour and an appearance in the movie musical version of the Beatles' "Sgt. Pepper's Lonely Heart's Club Band," Aerosmith practically ceased to exist.

But with the release of "Permanent Vacation," Aerosmith began a slow, but steady climb back to respectability. The singles "Dude Looks Like A Lady" and, more recently, "Angel," are catchy, if somewhat predictable pop standards that shot the band back into the top 40.

And it must be noted that the new tunes seemed to elicit the strongest response from the audience. But there's something lacking in their more recent efforts, something I can't quite put my finger on. I think a big part of it is an unwillingness to take the sort of chances with the music that once propelled them to fame. Although once a trendsetter, Aero-smith now seems to be playing the "me-too" game with the myriad of heavy metallurgists vying for their piece of the action.

What's puzzling about Aerosmith is that they still show evidence of having the wherewithal to transcend their contemporaries. Vocalist Steven Tyler's gravely voice, though technically limited, served him well for gritty rockers like "Walk This Way" and "Last Child." He was also effective on slower, more melodic ballads.

Guitarist Joe Perry, too, is a standout. He cranks with the best of them on songs like "Draw The Line" and especially "Back In The Saddle" with it's chunky, Jimmy Page-inspired guitar riffs. He also deserves recognition for having the intestinal fortitude to lay down his electric guitar, if for only one song, for a short acoustic set with Tyler crooning beside him.

Novelty counts at a rock concert, so it's only fair to credit the band with doing at least one thing I've never seen before. When drummer Joey Kramer stepped out from behind his drum set and turned himself into a human percussion instrument, I at first thought it was taped pounding to which Kramer had carefully matched his drum strokes. But I soon realized he was actually playing. Kramer somehow had his drum sticks wired for sound so no matter what he struck - whether it was a piece of on-stage furniture of his own thighs - it sounded as though he were beating his drums. It was quite a spectacle, giving new meaning to the term self-flagellation.

Technical wizardry aside, Aero-smith showed they can still rock with alacrity, although one can only hope they can some day recapture the inspiration they had 10 years ago.