I'm not a fan of dealing with cars in the city. If I were in your shoes I'd live in chestnut hill where there is more street parking. Plus you get a taste of the city and have two train lines that will get you into the city in about a half hour. You have the driving convenience to get to plymouth meeting, king of prussia, glenside, jenkintown, east falls, manayunk,mount airy etc and you have a 2nd car if your wife takes the train. I'm pretty sure one of the trains takes you right into university city.
If paying to keep your cars in a garage is reasonable, I'd rather live in center city than west philly. However, parking in west philly is easier and there are some pretty areas that are more quiet than Center city.
West Philly always felt like you could end up in some shady areas fast. In my experience it was cheaper than Center city, but there were plenty of times I looked over my shoulders when walking...wife got robbed at gunpoint, house burglarized, friend robbed at gunpoint on front porch in daylight, person 10 minutes ahead me was stabbed on drexel's campus, 5 or 6 kids tried to mug me once... etc.
At the same time, my first year in center city 4 people were killed on the street I lived on (13th street). But most that were people attacking people they knew.
I can't really vouch for the other neighborhoods in the city as far as living. I don't think I'd enjoy living in South Philly or Fairmount as much - less charm in my opinion.
I had a friend that lived at front and callowhill. Plenty of street parking and it's fairly close to the spring garden subway station for your wife.
Its also a bit desolate at night and might creep your wife out if she's walking home when it gets dark early during the winter. It didn't really have the convenience of walking 3 or 4 blocks to a choice of 10+ restaurants either.
"Believing is seeing" - paraphrased from PH