i spent thankgiving 2009 week in healdsburg and ate at the following:
cyrus- great food, vegetarian tasting menu is an option, really expensive. great service but some upselling goes on that can be annoying if that bothers you. they try and sell you caviar and champagne from the caviar cart to start for example. a nice splurge meal if you are up for it.
madrona manor- beautifal older victorian mansion just outside of town. i think this place has a michelin star. we ate thanksgiving dinner here, so didn't get to see the regular menu. i thought this place was wonderful and would love to return.
willi's- the santa rosa location may be good but the healdsburg location was a disappointment for me. oddly, for a wine bar and considering it's in wine country, the wine list is boring. i drank beer. food was decent.
bistro ralph- right on the square and lots of fun. i love this place. decent wine list and i am sure they can have vegetarian options. in december it is likely to be full of locals. the bar next door, pete and zekes (?) is a cool place to hang out if your table isn't ready.
oakville grocery- on the square with lots of options for take out.
two excellent bakeries. one is on the square, one just off the square near willi's. worth checking out.
small but excellent cheese shop called"healdsburg cheese" i think. good selection and knowledgable staff.
outside of healdsburg in geyserville is a excellent place for pizza. i will dig up the name for you. i think its called dante's. one of the best pizza's i have ever had.
good taquerias in healdsburg too. one across from oakville grocery is excellent.
we didn't eat at barn diva but the bar is really nice for a cocktail if you need a break from wine. although i am sure they have good by the glass selection of wine. next door is their home furnishing shop which is worth a look.
not wine or food related but, go for a hike in the alexander forest. 20 minute drive from healdsburg this is a redwood forest that is beautifal.
hope this helps.