There is a nice basic link building thread at WebmasterWorld on the topic of reciprocal links.
In this thread, SEOs are talking about the right of SEO companies to require their clients to link back to them. Many believe this is not a professional practice, while others don't think it is a big deal. Either way, that topic of debate is not my point for covering the thread.
My point for covering the thread is to say that not all reciprocal links are bad. Naturally, if you link to someone, they may take notice and link back, if it makes sense. It happens all the time over here. In fact, I may link to a thread at WebmasterWorld, say something smart (on a very limited occasion) and WebmasterWorld may link back (rarely, but they may) noting my comments or additional information.
But when reciprocal linking becomes unnatural, that is when you have to worry.
So don't spend too much time worrying about if it is a reciprocal link and just build a great site.
Forum discussion at WebmasterWorld.