You want a red bike. They go faster!

I 2nd a Fuji. They make a decent bike and they aren't quite the steal bait other brands might be. Though, I think it also matters where and how you lock your bike up. If it is sitting on a rack all alone, and with a flimsy lock, I wouldn't expect it to be there upon your return. However, if you park it with other bikes, and use at least 2 locks (one of them being a very sturdy Ulock), I think you will be just fine. I actually really like this lock myself. It takes up less frame space than a Ulock.
ABUS Bordo 6000 (Medium) - Brands Cycle and Fitness

As for SS/geared, I would go geared. A big shopping trip can make any bike seem heavy and cumbersome. Also, IMHO you should always get the bike that offers the most bang for your buck. If you can afford that better groupset, go for it. It is always less expensive to get the next model up with the better group than to upgrade it later.

Also, I don't think this has been said yet: but going carless - learn how to do your own repairs. Nothing sucks like having your bike be out of commission for a few days while it is in the shop.