I had dinner last night in Arnold at the Snowshoe microbrewery. The food was decent pubfood and the beer (I had their porter) was excellent. The service was very slow though quite friendly.
If you want a really excellent meal, stop 15 min. earlier in Murphys. We had lunch today at Grounds on Main Street (the single commercial street, and the commercial district is about 5 blocks long, don't worry, you'll find it. Grounds was outstanding, a definite place to return to, & I'll try to do a full review when it's not so darned hot!
If you're coming up Hwy 4 from the valley, taking Murphys Grade Road off 49 is a nice short cut and takes you right into the Murphys business district. Try to spare some tome for wine tasting, too, this is a significant wine region (url for one of the local winerys below).