Montparnasse or Bastille?

The Gaite metro area is a good location for getting around Paris as it's just a short walk to Gare Montparnasse which has 4 metro lines running through it (you can go direct to the Eiffel Tower or Notre Dame), plus the Air France bus from CDG stops at the station and trains from the station go to the Loire Valley(Tours). I sound like a realtor.... location, location

Ledru Rollin is handy for the Bastille and even Marais areas or in the other direction Gare de Lyon. I particularly like the Aligre area in the adjacent 12th with a daily market (except Mondays.) However the LR metro station is on a single line which means making transfers at the next stop, Bastille, for many destinations.

This is a tough choice, the Montparnasse area is not one of the most interesting in Paris, but being near a major metro stop with many lines is a huge bonus. Being on a stop with just one line can be insanely frustrating if you're relying on the metro a lot to get around. So I'd probably go with the former.

I agree that Montparnasse is not the most exciting part of Paris, but it is very Parisian in that there aren't a lot of tourists who stay here. We stayed in a hotel on the other side of the cemetery from Gaite in the Raspail area. That said, along Blvd. Edgar Quinet they have a nice antiques/flea market on Sunday mornings and a food market on Tuesday mornings. And window shopping among the cemetery goods shops along Edgar Quinet is interesting in a sort of macabre way. (my wife and I both really like the ceramic flowers they sell for putting on graves) The metro stops in the area, especially Montparnasse, are very convenient and there is a big shopping center in the bottom floors of the Montparnasse tower should you need something. There are a lot of restaurants in the area and most of the ones not on the main boulevards are not at all touristy.

We stayed in a nice one-bedroom apartment in the 14th, on rue du Chateau near rue Raymond Losserand. The metro stop was Pernety, one south of Gaite, and we found it very convenient for sightseeing and not overrun with the likes of us (tourists, ugh! ;) ). Easy walking to rue Daguerre street market, Montparnasse Cemetery, RER at Denfert-Rochereau, and the often-despised-but-also-underrated-for-the-view Tour Montparnasse, which provides a birdseye view of the city (including the Eiffel Tower) without the hassles of getting up the ET. I have walked around the area of Ledru Rollin metro but not stayed there, I thought it interesting but denser and perhaps harder to find a quiet place to sleep than Montparnasse. Proximity to Bastille is a plus though. I doubt if you could go seriously wrong with either area.