POP/ROCK. Throwing Muses - University (Sire/Reprise): This group,. fronted by singer-songwriter Kristin Hersh, has proven surprisingly durable. Now operating as a trio (the other members are drummer David Narcizo and bassist Bernard Georges), this latest release features some of their most accessible music yet, including the catchy ``Bright Yellow Gun'' and the enchanting ``Shimmer.'' The lyrics are ethereal and the grooves are downright funky. This is the kind of disarming, moody album that gets more captivating with each listen. JAZZ Toots Thielemans - East Coast West Coast (Private Music): There are 10 albums out by harmonica legend Toots Thielemans, and if you get one, you're probably going to buy all of them. Toots is the master of the instrument, although there are some jazz purists who still won't take the harmonica seriously. This new album is relaxed and charming, with more time given to improvisation by the considerable accompanying talent - John Scofield, Brune Barth, and Joshua Redman among them. The rendition of ``A Child is Born,'' accompanied by Herbie Hancock, is sweet and simple, and makes you wish you'd spent more time trying to learn harmonica. FOLK. Dar Williams - The Honesty Room (Razor & Tie Music): In her quiet moments, Dar Williams sounds a bit like Joni Mitchell. At other times, she defies comparison. This debut album captures the appealing soprano and unassuming demeanor that have made Williams a favorite in coffeehouses across the country. From the twangy ``Travelling Again'' to the rolling ``Alleluia'' with her near-yodel, Williams's voice remains the focus. But it's her songwriting that has shot her to the top. Her ideas on coming of age in nuclear times, childhood memories, and love make her lyrics worth a careful listen.