Monica had one of my favorite premiums last year, a 2-disc collection of male vocalists called BRIDGE OF SIGHS. Wonderful rainy-day music, all jazzy and folky and smoky. The (great) title of this year's premium: THIS TIME THE DREAM'S ON ME. I'd recommend that one.
Bill Kelly is a no-brainer for me every year. Great 60s rock obscurities.
I'm always a fan of the thematic premiums. Liz Berg is good at these and Therese's looks pretty fun too.
The station's great new old-school C&W show, Toothpick Rhythm, is putting out it's first premium this year.
I find a good rule of thumb for premiums is, if you don't know what you want, go with whatever gets you the most. 2-disc sets, MP3/DVD discs, etc. Also, you can never go wrong with a T-shirt. Never.