We've witnessed a year now of the kinder, gentler, more confident, more sleekly tailored, CBS Dave. But traces remain of the awkward-adolescent, NBC Dave, who gawks at supermodels, pulls Mary Tyler Moore onto his lap, and generally gushes over his female faves. As he approaches his Aug. 30 CBS anniversary, Letterman has lately been especially effusive.
*To Jamie Lee Curtis: ''Wha-hoo, man, I'm telling you something, that is one happenin' dress.''
* To Rosie Perez: ''Man, you couldn't look more summery.... There's something very sweet and appealing about you. You're just a lovely woman.'' *On Julia Roberts: ''She's a very nice woman, very sweet, very kind, very thoughtful.''
* To Penelope Ann Miller: ''You want to go? You and I will go and see Streisand.''
* On Mary Tyler Moore: (To Rob Reiner, who said, ''She is (beautiful) now, she was then.'') ''I think she's even better-looking now.''
* To Mariel Hemingway: ''We make a charming couple, don't you believe?''
* To Kate Nelligan: ''Kate, you're charming and delightful as always.''
* To Teri Garr: ''You smell nice, that's good.''
* To Susan Sarandon: ''You look wonderful. You look What are people laughing about?''