Be sure to consider all 3 main taxes: 1) transfer tax (4% in the city, generally 2% outside but there are exceptions) -- a one-time tax that can be significant in higher price ranges; 2) income tax (3% in the city, generally 1% outside but can be higher, especially in the South); 3) property tax (generally 100% of assessed value, but assessments can look "random" and are a continual source of controversy and court cases. Currently they're pegged to 2002 valuations, pending further court action.
Here's a complete list, courtesy of Keystone Closing. Keystone also has information on occupancy permit and dye test requirements, title insurance rates, etc. (Keystone is a closing company affiliated with Coldwell Banker.)