I'm here to bring some obscure titles.. Tokyo Xtreme Racer 2. Incredible japanese street racer, love the soundtrack and the atmosphere. Can be played for a looooooong time (not just because of the amount of content, but the tiny amount of money winning a race gives you lol) Airforce Delta. Essentially an Ace Combat clone by Konami, but damn it is a good one. The soundtrack is very arcadey, full of synth goodness, and honestly the game plays incredibly well. Metropolis Street Racer. Very competent racer with tons of content and a very flexible way to adjust difficulty. And c'mon, we got RICHARD JACQUES on the soundtrack. Bangers. It'd be pretty neat if a hypothetical DC mini could implement 16:9 patches, but also support 4:3..
For an unreleased game bonus - I'd love to see Dee Dee Planet (spiritual successor to Chu Chu Rocket).
Not mentioned so far but should be: Soul Calibur is a must. Highest rated game on the system, and was definitely a memorable entry in the series. Its third party but was also considered by many to be the best game on the console. Also Sega Swirl! Surely I'm not the only one with fond memories of this freebie. Sega Ga Ga would be really nice to see released internationally as well. (Okay was mentioned still going to echo it) PHANTASY STAR ONLINE HOW WAS THIS NOT MENTIONED Virtual On:OT if they can figure on a twin sticks solution they would be willing to ship Sega Bass/Marine Fishing were also great US release of the light gun... Beyond that I think the really important Sega franchises are covered. Other nice-to-see third party games would be: MDK (Wouldn't hold my breath because EA) Half-Life (I imagine Gearbox would be the obstacle here) San Francisco Rush 2049