When I first read what Ore no Imouto was about, I had no doubt that the ending would include Kyousuke and Kirino in some (w)incest relationship but now that it seems to be avoiding that route, I can't believe that Kyousuke is letting Manami slip away. She obviously leaves him hints at the park, and my favourite Manami scene:
I'd love to see this develop into something bigger, but I highly doubt it seeing that there's so little love for Manami x Kyousuke and it's never the childhood friend
Oh well, maybe in the PSP game...