Hi cycleheimer, Baltimore is great for bikers if you measure against what it was like 10 years ago. If you measure against NYC, probably, not so.
That said, bring the bikes!

There is a lot of downtown harbor area touring you can accomplish safely. Also, you'll find several trail networks- Gwynns Falls and Jones Falls very nice and safe.
If you're up for riding out of the city to check out the environs I recommend it. North of the city you'll find beautiful horse farms. West, hills and historic mills. South is flatter and a combo of farms and suburbs and east is a myriad of rivers and ports.

What kind of cycling are you interested in? Mileage? Speed?