So it sounds like a 1/2" breaker bar is a necessity. Beyond that, there's differing opinions between what drive sockets to use but adapters are worth using. I don't see the point in carrying 1/4" 3/8" and 1/2" for everything, but some people seem to go with strictly 3/8" and some are saying everything. I'm still not sure which way I would go with that.
When I get the time I'm going to start making a list stuff from Harbor Freight. The other concern is that since this will be a trunk kit, I don't want to spend so much that I'll be upset if shit gets lost/broken/stolen, and since I won't be using it nearly as often as my garage tools I won't be so concerned that they be nice quality.
In other news, I noticed you can get a lot of Snap-On tools from Amazon. Other than that and Ebay, do they or MAC or any of the other high end tool makers that are normally just sold off trucks sold in any other venue where non-professionals such as myself could pick them up, and still be able to make warranty claims if need be?