I'm going to say single digital title. I say this because I like to collect (from ebay or wherever) the physical classic psx title and keep it on my shelf. It might be cool to have a collection on a disc, but I think game discs will just be totally gone in 5 years.

It's something that's going to be a hot topic for a while.
Personally, I'd like to have a compilation disc (like the Sonic Mega Collection that SEGA just did), but I consider myself a collector of sorts (I have a lot of the originals on cartridge/opticals).

As much as I'd love to see physical media get completely phased out by digital downloads, I think that physical media will be around for a long while unless the publishers force everyone into a digital platform.

I love being able to download my old favs but call me old fashioned...I want discs!