nando’s extra hot peri peri sauce.
haha.
…and anything else that goes with sticky white rice. 
I like mayo with lots of different foods.
Heinz ketchup is damn good too.
Is salsa a condiment? Then that’s it.
If not, then pepper.
Hellman’s Mayo. I only use it on sandwiches, but boy do I love it on sandwiches.
Crystal. A little milder, I can still taste the food.
Peace,
mangeorge
Also, I really like Anchor Buffalo Wing sauce on just about anything.
Oh hell, All the above. Including mayo.
Peace,
mangeorge
Horseradish!!
Mix it into mashed potatoes, slather it on a sandwich, dollop in on a dog (hot)!!
First of all, if a steak needs sauce, it’s a piece of shit steak, a la Golden Corral.
I use Miracle Whip on most sandwhiches and Tuna/Chicken Salad. Drain Bead finds me to be a heathen for this. Whatever, I love it.
On a steak, I need horseradish. Not horseradish SAUCE, real horseradish, preferably freshly grated.
On a hot dog or with my corned beef and pastrami, it’s gotta be Spicy Brown Mustard. Gulden’s is just dandy for this.
A burger is best with NO condoments. A properly cooked burger should be juicy on its own.
I love ranch dressing on dipped veggies and salads.
Okay… I think that’s everything…
Yer pal,
Satan
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Duke’s Mayo
Heinz Ketup
Any kind of mustard
In that order.
Cajun seasoning. On anything. Especially with butter on corn on the cob grilled over a wood fire while camping.
The only way to have a burger is to cook it medium rare, then top it with cheddar, sauteed mushrooms and onions, and A1. At that point, it’s so juicy, you can barely eat it with a bun.
I completely second Satan’s nomination of horseradish (and NOT the sauce–even horseradish can’t save what was originally Miracle Whip), especially on rare steaks. I also love it on any sort of roast beef sandwich. Beef on Weck…mmmmm…
Horseradish mustard, or if I can’t have it, spicy brown, is the only condiment I will put on most cold cut sandwiches or hot dogs.
I also, ironically, love Thousand Island dressing on fries. I make it myself, by mixing mayo, ketchup, and relish. None of that bottled crap. Gravy on fries is also heavenly.
Sour cream and guacamole are necessary on damn near anything Mexican.
I put tabasco in ramen noodles. They’re 10 times more edible that way.
Can’t stand ketchup on its own or Miracle Whip. I can stomach mayo, but only in the smallest of quantities–it’s one of those things that’s better IN stuff than it is ON stuff.
Nuoc Cham
On turkey sandwiches, burgers, in ramen soup,
on take-out chinese, a glob on the side of
home-made stir-fry, on pad thai, on chicken, steaks,
chicken wings, etc etc etc.
Second favorite condiment is probably Heinz Ketchup.
Drain Bead -
Beef on weck and gravy on fries?
Are you by any chance a Western New York ex-pat?
How about a nice chutney?
With roast beef or roast lamb it is, by far, the best condiment.
No, but I got all of this from my stepfather, who is from Buffalo.
That and the whole Bills fan thing.
That explains a lot! 
Heinz ketchup.
Miracle Whip.
French’s yellow mustard.
Salsa.
On different things, of course.
Tie between ranch dressing and tobasco sauce. Actually, it’s whichever one is cloer to me when I open the fridge. And when I dine out, I ask for both.
Okay, I’ve had this discussion before, and its quite extensive. First, you must decide what makes a condiment great. Is it it’s flexibility and ability to be good (and by “good”, I mean “able to vastly improve and add to the flavor of the food product it is being added to”), or is its exclusivity (in other words, there is one food that just cannot be consumed without this certain condiment)?
The first of these HAS to go with butter. Butter by itself is not all that good. Not a great deal of flavor, not a lot of pizzazz. But what roll is not improved about 752% when you add nice melty butter to it? Butter is incredibly versatile, and when added to the correct things makes an enormous difference.
In the second category, I would like to nominate sour cream. I know its not entirely exclusive to one particular food, but I just can’t seem to enjoy “Mexican” food without it.