While I'm not a fan of digital content, I'm thinking of purchasing one, or maybe two of the compilations currently available for the PSP digitally to play on the PS Vita when I happen to be out and decide to not want to play the Vita game currently in the system. There are other compilations, but I've only listed these because I think they're the best value and have the best games.
Sega Genesis Collection
Alex Kidd in the Enchanted Castle
Altered Beast
Bonanza Bros.
Columns
Comix Zone
Decap Attack
Ecco the Dolphin
Ecco: The Tides of Time
Ecco Jr.
Flicky
Gain Ground
Golden Axe
Golden Axe II
Golden Axe III
Kid Chameleon
Phantasy Star II
Phantasy Star III
Phantasy Star IV
Ristar
Shadow Dancer: The Secret of Shinobi
Shinobi III: Return of the Ninja Master
Sonic The Hedgehog
Sonic The Hedgehog 2
Super Thunder Blade
Sword of Vermilion
Vectorman
Vectorman 2
Virtua Fighter 2
Astro Blaster
Congo Bongo
Eliminator
Space Fury
Super Zaxxon
Capcom Classics Collection Remixed
1941: Counter Attack
Avengers
Bionic Commando
Black Tiger
Block Block
Captain Commando
Final Fight
Forgotten Worlds
Last Duel
Legendary Wings
Magic Sword
Mega Twins
Quiz & Dragons
Section Z
Side Arms: Hyper Dyne
The Speed Rumbler
Street Fighter
Strider
Three Wonders
Varth
Capcom Classics Collection Reloaded
1942
1943
1943 Kai
Commando
Eco Fighters
Exed Exes
Ghosts'n Goblins
Ghouls'n Ghosts
Super Ghouls'n Ghosts
Gun.Smoke
The King of Dragons
Knights of the Round
Mercs
Pirate Ship Higemaru
SonSon
Street Fighter II
Street Fighter II: Champion Edition
Street Fighter II Turbo: Hyper Fighting
Vulgus