Count me as “as many as possible via download”. I only buy physical discs if I have to, for the opposite reason that many of you cite:
I am ALWAYS losing discs, CD keys, etc. I can’t play several games I own anymore without cracks because I can’t find the CD key, despite owning a legit disc. I can’t play Battlefield 2 because my Disc 1 is missing (the others are right there in the box, of course).
I think I bought Bioshock, C&C3, and that’s it on physical media this year. Compare to Warhammer Online, several Steam games, etc.