I have a friend I believe to be ISTJ. We've been friends for a long time and get along well overall.
We're both introverts and there are a lot of similarities there in the way we interact in that way. We both have a fun time picking apart things we find ridiculous. We're both logical and thinking types and are fairly unemotional. We have a similar sense of humor, like the same kinds of movies, have similar interests. We can have fun together when just hanging around each other, we don't need to be chatting about the weather, plus neither of us cares about small talk! We like to jab at each other to get reactions, using sarcasm and witty banter, all in the name of fun.
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I agree with what was said above! My wife is an INTJ (and proud of it!) and we've been married for 19 years. We have an excellent relationship, we give each other space while we do spend time together talking about all sorts of things, from philosophy to business, from how to raise our three boys to cracking each other up with the latest gossips! From what I read, the major problem with an ISTJ-INTJ couple is the potential dullness of their life. That might be true, but I'm not sure what do people expect from a good relationship... continuous drama, soap opera? Thank God, I'm spared of such thing! We've had our courtship, we married, and we kept living! The only arguments we have is not about something domestic but rather different ideas about we both feel strongly (could be anything!). Once an INTJ forms an opinion, that's it, there's nothing to convince them to the contrary, while us, the ISTJs, we'll listen to a logical argument and if it makes sense, we are willing to concede and change our views. I've learned to stop arguing if I see that it goes too far, even though I know that I'm right (no counter argument will make my INTJ change her mind!). In any case, I'll let her know that I'm not arguing anymore because she doesn't get it

This makes me think that two INTJs will have a problem living together as none of them would be willing to concede if the happen to be on opposite sides.
One thing that may help an ISTJ-INTJ relationship is how the INTJ sees his or her ISTJ partner. My wife said that she decided to marry me because I was the first guy that she perceived as smarter than her. How much of that opinion is still valid today... that's subject to debate, however, if the ISTJ keeps impressing the INTJ with his or her "smartness" the INTJ's sense of superiority will be held in check and the relationship will be a healthy one, peer-to-peer. This is especially true when SHE is an INTJ.
The "traditions" thing... true, my wife hates every one of them: Christmas, Thanksgiving, birthdays, you name it. While I'm not a big fan of it, I see their values in keeping some sort of ritual in our life - people get comfort from rituals. The kids get excited about all of them and I hate to be the Grinch! Here I get free hand in organizing whatever I want... she would even decorate the Christmas tree
In conclusion, ISTJ-INTJ can be great partners, but then, how can an ISTJ fail at anything...
