** Whitney Houston, "The Greatest Hits," Arista.

As a singer and record maker, Houston has never been known for restraint, so it shouldn't surprise us that her first "greatest hits" album is a sprawling 2 1/2-hour, two-disc affair. That's disappointing for two reasons.

Rather than offer casual fans a value-packed, single-disc survey of Houston's biggest hits, the collection is a bloated mix of Top 10 singles, remixes, rarities (including the 1991 Super Bowl version of "The Star Spangled Banner" and the 1988 Olympics theme, "One Moment in Time") and four new tracks.

The new tracks are the second problem.

Ever since writer-producer Babyface helped inject some vocal character and warmth into Houston's work on the "Waiting to Exhale" soundtrack in 1996, she has been moving in a more satisfying direction. The grittier, more contemporary touches on 1998's "My Love Is Your Love" album and her subsequent tour were especially encouraging. She finally seemed to be using that magnificent voice in truly interesting ways.

But the new tracks are mostly flat.

The duet with Deborah Cox on "Same Script, Different Cast," strives for, but falls a tad short of, the kind of convincing romantic tension that Toni Braxton regularly achieves. And even producer David Foster and writer Diane Warren--the team that was responsible for Braxton's classic "Un-Break My Heart"-- can't make the pairing of Houston and Enrique Iglesias generate any convincing heat in "Could I Have This Kiss."