Pretty much anywhere in the city is only 15-20 minutes from the airport.
For garages, there are some buildings with garages (would you feel comfortable leaving the car in a parking garage; e.g. renting a spot?), or if you can find a house for rent that actually has a garage in the city...that will be much easier in the 'burbs. Many, many people on here will tell you to ditch one of the cars since parking 2 in the city can be rough. Based on your other preferences, it seems to me that you would be happy in any of the neighborhoods around here. I guess it just depends on where there are more places that have garages. I don't know if I've been of any use, but it's hard to give you specific ideas since you seem extremely flexible; I'd say get some ideas on general feel of neighborhoods and then base your search on that.
I'm sure others will tune in shortly with their preferred neighborhoods. I'm in Fairmount and there are very few houses/condos for rent here with garages (possibly in Westrum's Brewery Town development) and a few bigger buildings, and there are some parking garages (which is why I asked about that). The parking garage deal holds true for a lot of Center City as well.
Best of luck.
Remember, no matter where you go, there you are. -- B. Banzai