Dalma is a must visit restaurant for Oriya food. Beware of its mispelt copycats - there are even a couple of them right by it! We ate there ate least once a day for our stay in Bhubaneswar. Also, Bhubaneswar has great street food. The dahi bara aloo dum is great, the chaat is amazing, the ghugni is delicious , the jhal moori divine, etc. Also Hare Krishna restaurant near the train station is good quality, though it is slightly expensive.
Oh, and do not miss the delicious Oriya sweets here!
Chowhound is a food website so I won't talk about tourist attractions. But if you look online you will see that there is much to visit :)