I agree with Gerry. It's hard to make recommendations with so little info. But, I'll try to generalize and over-simplify the area surrounding Baltimore. The following descriptions are just my opinions...
BALTIMORE COUNTY: The most populated suburb, most diverse.
The I-95 corridor north of the belway (I-695) is nice, middle to upper middle. Affluence increases as you increase distance from the beltway.
The I-83 corridor from the beltway to PA line is a little more expensive than the I-95 corridor. IMO, it's a little more "preppy." This is horse country. Private schools, etc. This has Dulaney High School (public), one of the best schools in the country.
The I-795 corridor has middle and upper middle, too. However, this area seems to have a higher proportion of ethnicity than the first 2. After caucasion, the population is known for its Jewish and African American cultures. Pricey real estate, about the same as the first 2. Pikesville HS is here...another good one.
The section between I-70 and I-97 is good, solid middle class. White collar and blue collar, black and white. Older neighborhoods, smaller homes. More affordable.
HARFORD COUNTY
Very nice, upper middle. A lot people who used to live along the I-95 corridor in Baltimore County seem to "move out" to Harford County. Nice area that's more affordable than sections closer in. Rural, becoming suburban.
ANNE ARUNDEL COUNTY:
It appears this is where Gerry is from. So I'll let him elaborate if he wants to.
There's a lot of watefront here, so that makes some real estate expensive. The northern section of the county has some older suburbs.
HOWARD COUNTY
Other than Anne Arundel waterfront, this county has the most expensive real estate. Very expensive. Highest household incomes in the state. Best schools in the state.
CARROLL COUNTY
This is where I live. It's probably the most rural of the counties around Baltimore. Least expensive (but that's relative...the whole area metro area is expensive). 95% White. 75% Republican. Rednecks. Excellent schools.
BALTIMORE CITY
The most affordable housing in the area. But, the highest taxes. Poorest schools...very very poor. Typical city problems with crime and drugs.
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One thing you may want to let your firend know is that Maryland defines its school districts by county. There are no municipal school districts. This is difficult for some people to understand when they move here from out of state. 25 high schools (and their feeders) and 150,000 kids could be in one district.