There are two schools of thought to this question, kind of like Economics with Classical and Keynesian theory. Except not at all similar since both of those were attempting to explain market systems and here, the answer is either yes or no.
Let's start with the traditional answer - yes, you should give him a shot. By your own description, he sounds like a great guy. Perhaps you don't feel the spark but it can grow. Right? I mean, men grow on women all the time. Isn't that the premise that 99 percent of all romantic comedies are built around? Persistance? The big pay off??
On the other hand, if there's no spark there, and you believe in spark, then I'd say no. Now, it is entirely possible to put too much stock into the initial spark since you never know what can happen. He might very well say or do something that you think is absolutey adorable and the next thing you know, you've stars in your eyes for him. I've seen it happen before. It's happened to me before. It is also the same premise that the other 99 percent of romantic comedies are built around. My data may be a little bit off today.
Anyway, my suggestion would be to take him up on the offer. It's just a date. If there is nothing, well, you took a shot on a great guy but it won't work. As long as you keep it on the up and up since you two have to deal with one another. Be nice and be honest. That way no feelings hurt and he doesn't end up Urkeling your set.
Its doesn't hurt to go out on one date. If you don't feel anything after that, then you might want to move it into a friendly relationship. You may even be able to finagle one date into a mistaken "friends going out, no romance involved whatsoever" situation later. Obviously, being honest with him about the lack of spark ASAP is advisable.
If you can hold out for a kiss, that might be a good indicator. I good kiss can go a LONG way to making up for a supposed lack of chemistry.
Mr. Jackson, as an economics major, you are my new favorite person. Not just for the economics reference, but for actually knowing about Classical/Keynesian theory. And bonus points for spelling Keyensian correctly! ;)
I think the key-word that people are missing here is "relatively attractive". Obviously, this person is indicating that she/he thinks some people would consider this person good-looking, but isn't really his/her type. If you're saying you aren't attracted to this person, than perhaps it's best you don't get this person's hopes up. Just say you'd totally go out and have drinks with this person, but you think it's best you don't start anything being you have a professional relationship that a personal one would interfere with.
Just make sure this guy isn't trying to climb the ladder by climbing into your pants...