There are those who feel Ottorino Respighi, whose centenary is being observed this year, was at his best when he was not writing original music but arranging material by other composers. Surely the score he built on Rossini themes for the ballet "La Boutique Fantasque" is one of the most delicious of all such concoctions.

It is, however, hardly ever heard live, since the ballet is not in the active repertory now and the music, considered too lightweight for "serious" concerts, is somehow overlooked by programers of pop concerts, which have assumed a different character from the one that prevailed, say, 20 years ago. It also is less abundantly represented on records than one might have assumed, and is seldom recorded in full. An uncut performance by the London Symphony Orchestra under Lamberto Gardelli has just been issued by Angel, filling both sides of SZ-37570.

While this is the most attractive version of the full ballet score since Ernest Ansermet's monoral recording with the same orchestra for London/Decca nearly 30 years ago, it also is a reminder that Ansermet was in a class by himself in realizing the charm and elegance of this music as well as its more obvious color. The new Angel recording is handsome enough in its own right, but ultimately it fails to make a convincing case for two sides' worth of a score that fits so well on a single side with judicious excision of some repetitious passages.

Gardelli's easygoing way is preferable to Solti's hard-driven approach on Lond STS-15005, but both Antal Dorati and the late Arthur Fiedler, in their respective single-sided recordings, project more of the wit and sheer sparkle that are the essence of the piece. Dorati's performance, a little straight-faced but quite stylish, is paired with an absolutely stunning account of the obvious companion-work, Respighi's "Rossiniana" (London SPC-21172; cassette SPC5-21172). Fiedler's -- generally brighter but older recording -- comes with a similarly substantial sequence from the Offenbach/Rosenthal "Gaite Parisienne," on RCA's low-priced Gold Seal label (AGLI-2701; cassette AGK1-2701).

Columbia has announced another "Boutique Fantasque," with Andrew Davis conducting the Toronto Symphony Orchestra, for release in a few months, but has not specified whether it will be cut or uncut. In the meantime, this young conductor shows a nice flair for ballet music in his new recording of Tchaikovsky's complete Nutcracker score with his Canadian orchestra (Columbia M2-35196, two discs). The familiar music is well paced, well played and sumptuously recorded, though there are minor flaws (e.g., clangy celesta in the Sugar Plum Fairy's music, too-close placement of the children's choir in the Waltz of the Snowflakes) and a general lack of real atmosphere that render this presentation less than fully competitive with the best full-price version.

Indeed, even at "half-price," old Ansermet comes into the picture again, and this time not just as a memory. His unfailing elegance and all-round evocativeness really tell, and his recording, first issued more than 20 years ago, conceals its age well enough to make London set STS-15433/34 a genuine bargain. So for that matter, is Gennady Rozhdestvensky's recording, of similar vintage, in MHS 3888/89, a set not only less costly but slightly smoother-sounding than Columbia's processing of the same tapes in M2-33116.

(The annotator for the Davis recording writes that Tchaikovsky used the celesta in his early opera "The Voyevoda." Actually, it was in the much later tone poem of the same title, unrelated either musically or programmatically to the opera, that Tchaikovsky first used the then-new instrument. It was, in fact, his displeasure with that tone poem that led him to produce the Nutcracker Suite, the only suite he himself drew from any of his three ballets; when he took "Voyevoda" off a program he was to conduct in St. Petersburg he still wanted to surprise his audience with the sound of the celesta, and so prepared the suite from the still unfinished ballet, placing the Sugar Plum Fiary's music near the beginning.)

More very familiar Tchaikovsky, the overture-fantasy Romeo and Juliet and the "symphonic fantasia" "Francesca da Rimini," may be had in another highly recommendable bargain reissue, in performances by Carlo Maria Giulini and the Philharmonia Orchestra (Seraphim S-60311). This may be the most satisfying of all such couplings at any price. The Romeo is especially compelling -- a beautifully balanced, straightforward reading in which the passion and drama take care of themselves.