"Instead - why not just build a really big magnet and just bring everything else to us?"
This little pearl of wisdom was imparted to me once by a drunken roommate. The idea itself is not particularly practical, but I think that it's an excellent example of the kind of thinking that the human space program is going to need if we're ever going to make much progress. We need to challenge every assumption and rethink every strategy constantly, and keep trying new and different things. Large, expensive, and comprehensive missions? Mars Pathfinder showed us that alternatives can be just as (or more) effective, at a fraction of the price. As we face the growing technological and conceptual hurdles of large-scale space exploration (and even colonization), of superluminal travel and life in space, we have to remember that the only way to get there may be to try something weird - or maybe just bring it to us instead.