Back in the day, I lived in
Sachsenhausen and got the 61 bus to Terminal 1 then got onto the LH Shuttle which goes directly to each building and as you'll get your transport costs probably paid (JobTicket plus cheap car rentals when needed), you might want to think about whether you need a car. Parking is also horrific in FFM and apartments don't generally come with car lots.
But I was
Systems, not
Passage.
Sachsenhausen has great transport links (train, bus, close to motorway), a decent big supermarket, running routes, plus some pretty good bars nearby. You can also get to other parts of the city relatively easily.
One downside: it can be an LH Ghetto precisely because it is so handy (but the local gyms etc also offer discounts if you show that badge).
Bornheim &
Nordend also popular with
Lufthanseaten.
Don't forget to use the LH Intranet, it's a goldmine of local info!