1) DOA3.1 because it's the "politically correct" answer the majority of the competitive community agrees with.
2) DOA Dimensions, personally because I have never beeen more confident in playing a DOA game before, even though it was on a portable. Obviously, I want the gameplay changed drastically, but full motion cinematics and a versus interface like the one in story mode for every match would KICK. SERIOUS. FUCKING. ASS. In fact, all future DOA games should have a versus bumper like that. It's little things like that which gives a sense of thrill for the upcoming match.
3) DOAX, preferably as a pack-in with another DOA fighting game. With Momiji and Rachel in the mix, online AND offfline multiplayer, Sega AM2 as the co-developer, refined gameplay inspired by Beach Spikers, some over-the-top elements inspired by DOA5 such as Power Spikes (which behave similar to NBA Jam's "on-fire" conditions) and cross-game integration with swimsuits (provided they go all the way with full customization), this deal can't be beat. Yeah I said it, fuck y'all, I'm still awesome.