Our closest "large" (read: not that large) grocery store, the Rewe in Das Carre in the Adenauerplatz, closed down for renovations about a month ago. This sucked. There are an Aldi, Lidl, and Penny conveniently located, and there are some small grocery stores in the Altstadt and a small one in the basement of Galeria Kaufhof in the Bismarckplatz, but most of these have shorter hours and more limited selections. Actually, our Rewe wasn't that great either. Most Rewes, like the one I always went to near class in Mainz or the one in Handschuhsheim that everyone's always recommending to us, are pretty alright. This one was kind of a crowded dump.
We have the same problem with grocery stores here that we had in Boston: namely, for the carless, it's not easy to get to one with a really big selection. We pretty much always need to shop in multiple locations. Here there's the additional problem that the produce at grocery stores doesn't seem to be that good. What you can get at the market is great, but that is only twice per week. Sometimes smaller produce stores have better stuff and bigger varieties. I can't think of a single store where we can get every food item we usually need. People are always telling us "oh, you can get X at ___(insert name of store here that requires a bus/Strassenbahn/bike trip to get to)___". This was always a problem in Boston too. And Chicago, come to think of it. It's nice to have a good store you can just run to when you think of a meal plan later in the day - trips out to the outskirts to the Giant Kaufland require planning. Unfortunately, planning is not my forte, heh.
Anyway, our Rewe reopened a couple of days ago and it's much nicer now! The selection is still not exactly amazing (can anyone tell me, is frozen corn sold in Germany? It isn't at that Rewe), but if nothing else, it's at least more well-organized, easier to get around with better traffic patterns, and the checkout is bigger. I think the produce section grew, too. They added a frozen section where the food is on shelves instead of in those trunk-like freezers - much easier to find things. Now let's just hope they improved in the meat section and manage to keep enough chicken breasts in stock (always a problem for some reason)! There have been other changes in Das Carre, too. The Italian restaurant/Eis joint that was next to Rewe is gone, with a bakery/cafe sort of thing in its place. The clothing store that used to be across from the Eis place is also gone, and the Turkish market next to it has expanded into that space. The Thai restaurant in there has cleaned up a bit too, with new furniture and signs, but the food still isn't that great. (It always smells freaking awesome, though.)
Now they just need to fix the intersection outside Das Carre, what a disaster that thing is....