It's pretty clear what Keima wants at the end.
Pretty sure she'll forgive him considering that last conversation. Not immediately, he'll have to work for it, and considering the end it seems like he'll put out at least some effort eventually.
The other girls will probably forgive him, but not without some pain. Especially considering the situation and how he pretty much saved the world, even if he was a bastard about how he went about it.
Some will probably remain friends with him, others will probably not want to speak with him. I doubt anyone is really angry with him considering all of them know about the situation he was dealing with. I really don't see the ending as a he's screwed type of harem ending. The only real bump I forsee for him is if Tsukyo's Goddess goes full on Yandere on him, and I think Tsukyo would reign her in at the end of the day, but probably not before Keima suffers a bit.
The endgame matchup is pretty obvious assuming Keima gets what he wants. Especially considering he ends up turning off his games and walking into the real world willingly. Though, I doubt that means he'll give up his addiction entirely. He has developed a liking for the real world at least, though he'll probably never admit it.
He's actually pretty refreshing as a harem lead character. He's neither stupid and overly strong, or a complete wimp emotionally.
Honestly, the full harem ending is fun to imagine, but it seems to me like the show itself does everything but hang neon signs around Chihiro that say "She's the Matchup" on them.