I prefer DD.

I like both options.

I'm only of those guys who love  building up collections.

First of, I hate downloading games. That's why I don't use Steam or download PSN or WiiWare Games.

I can get the same game from retailers at a cheaper price so there's no need for me to download PSP games.

I'm definitely a UMD persion myself. They're cheaper, more reliable (yes, I do trust myself more than Sony's network), and the physical collector in me like having them. I've got plenty of little cases that hold 5 PSP games, and they have belt clips, so it's easy enough for me to grab 5 (or 10) games and go.

OPP.

UMD, rather. I like having the case as well as the manuels.

UMD walks all over Digital Distribution cause by the time Sony announced going DD and puting psp games on psn i could get all those titles for less than 10-15$ while they were for 30-40$ on psn. and not to forget most of my games weren't even released on psn so far plus many newer games are not published on psn either. to me DD will be ok with PSP2 if they will sell new games for 20$, at worst 30$. 40$ for new UMD title is already pushing it and for DD is just a ripoff. i won't even start with Square Enix games or some Ubisoft titles that were priced on psn(and UMD) at 50$ and those were friggin Final Fantasy I and II remakes and stupid psp port of Tom Clancy's EndWar DS.

Well I like DD games, I like everything about them - except for the fact that I don't have the box and I'm scared I might somehow lose the game.

Now if you were able to still have UMDs but with the ability to install the game to the PSP then that would be perfect for me.

Both.

What media does the DS use? I am all for disc media but I dont like unique formats.

a form of solid state rom with some flash or EEPROM for saves in general.