How are you planning to commute, and how much space do you want? Almost everywhere in Montgomery County is really, really nice.
If you want to live closer in and have a large budget, you could live in Potomac or Bethesda. Potomac is pretty close to DC, but it’s wooded and full of huge houses with big yards. It’s very affluent and has great schools. You have to drive everywhere- there’s hardly any public transit, but nice bike trails and walking trails.
Bethesda has more of a “city” feel to it, but also very affluent. The houses are a bit closer together, but everything is a bit older so you’ve still got the shady, tree-lined streets. Most of Bethesda is close to the Beltway and/or public transit for an easy commute and it’s full of great restaurants and shopping. Many listings will say that they are in “Bethesda” when they are far north of all these amenities, getting more into Rockville.
Rockville is a little farther out but still very nice. Prices are a bit more reasonable here. Rockville has a very safe, suburban feel to it. You’ll find nice single family homes and townhouses, many shopping centers and Starbuckses, great schools and plenty of parks. The metro is centrally located but bus service out here kind of sucks. If you want to take public transit in you’ll have to drive to the metro and that gets expensive fast.
If you want to be in the western part of Montgomery County near the red line you could also go for Gaithersburg, which is a lot like Rockville but more spread out and a little less expensive. But rush hour in the DC area is terrible and you’re starting to look at a really bad commute. Any further out and the commute becomes prohibitive.
Fairfax County and parts of Arlington County are also very nice. The Vienna/ Tyson’s Corner area in Fairfax is full of great schools, shopping, and plenty of nice houses. It’s probably pretty similar to living in Rockville, but Tyson’s is a bit of a city in its own right.
Arlington has some very nice neighborhoods, especially in North Arlington, and it’s right next to the city. You can walk or take public transit everywhere if you want, there’s great shopping and restaurants, and very good schools. Many of the houses are older and have a lot of character.
Good luck on your move!