First, it is very difficult to live in Baltimore without a car. I hope that this fact will one day change, but for now, the public transportation is not the greatest.
Federal Hill is a good place for a 20-something. There are several other neighborhoods that might be a good fit as well. See this post:
http://www.city-data.com/forum/balti...more-july.html
Are you looking to buy or rent? I haven't checked craigslist rental ads in a while, but I believe a two bedroom rowhouse in Federal Hill or Canton starts at around $1400 and can go up from there depending on the house. If you're looking to buy, prices have definitely slid back some compared to this time last year.