Italian food is relatively fool proof, although ordering an entire pizza for one person can make for a somewhat lonesome, not to mention dangerous, evening, if you happen to possess that all important Y chromosome. Simple pastas, heroes and salads travel well and most neighborhood places do a pretty fair job at a reasonable price. Just make sure to order any salad dressing on the side, unless you want to spend half your evening towel drying the lettuce. Mexican food is fine but be careful when ordering anything that consists of mostly cheese and beans - they quickly congeal onto a Frisbee sized mass that resembles nothing so much as fake vomit. I find that it's best to order individual tacos with salad or guacamole, unless you're willing to bribe the delivery guy into picking up a bottle of Sauza and a few limes on the way over.
Indian food is great, as long as it is consumed in an authentic Indian restaurant.
Once you take away the Pier 1 decor and the annoying music it loses some subtle quality. Unpacking all those strangely textured and exotically colored items in the bright light of your own kitchen you notice that everything looks a little, well, too organic, if you know what I mean. You could of course try to recreate the appropriate atmosphere by turning the lights down and playing a Cyndi Lauper tape backwards, but my advice is to either brave the cold or wait till spring for Tandoori shrimp. But again there are only certain items that should be ordered to go. Sushi is great when its served by guys in pajamas wearing bandannas, but once you get it home it starts to look like something that should be thrown to you while you slap the backs of your hands together.