I build mostly 1/48, but, if the actual aircraft was a large bird (XB-35, XB-49, B-52, B-1, etc.), I'll build the 1/72 version of it, as the 1/48 version is either unavailable, or too big to display once built. I also occasionally build 1/32 kits, but only if the price is right for the kit. 1/72nd just seems too small (for me, anyway) for good cockpit detail, altough I've seen a 1/144 Harrier with cockpit detail that rivaled a 1/32nd kit. So, as a compromise between decent detail and display space, I stick with 1/48th. Currently, I have 98 1/48 scale kits out of a total of 116 unbuilt kits.