For luxury travelers, you should consider staying at the Marriott or the Hotel Yerevan Golden Tulip in central Yerevan. If you want to be a bit away from it all, there is the Tufenkian Avan Villa and the Latar. Outside of Yerevan, Tufenkian has hotels at Dzoraget in Lori, Tsapatagh near Lake Sevan and in old town Dilijan.
There is a very high end luxury adventure tour package to Armenia as well, by the internationally respected Wilderness Travel
For food, in Yerevan you'll want to visit Dolmama, the best of Armenia Dolma. Also try the Club, for more Western Armenian fare, and Mozarteum.