For me, it depends on the system. While I never pass up cheap loose games, for many systems I am a completist and will upgrade to complete games when I am able. I'm a completist for N64, Saturn, and Odyssey2 (PDF was SO RIGHT about O2 packaging), and pretty much any of the modern nonportables. Anything else like NES, Atari, Coleco, etc I am fine with loose carts. In fact for most of those systems I specifically trade away boxes and manuals to people who actually want them to be sure they end up in a good home. I may not want them myself but I do still respect their place in a collection.