Romance + slice of life + ecchi > romance > slice of life > ecchi > all.
The soundtrack for Yosuga no Sora is amazing. Double for Clannad.
5 stars = lots of tears/feels/lols/ecchi. Anything less probably didn't have enough of one or all of those. 3 stars or less and most likely I only watched it because I didn't have anything else to watch. No rating is either dropped/not worth the time to rate/watching.
I don't understand why everyone loves/compares everything to Code Geass? Yeah, it wasn't your average, and the main character used brains>brawn. But to compare Guilty Crown and any other 'mecha' anime is dumb. Guilty Crown is not a 'rip off' of Code Geass, and Code Geass shouldn't be the standard for other 'mecha'.
If I had to pick one show for everyone to watch, it would be Clannad. Hands down, no second thoughts.
Also, what is with the incest/twincest hate? It isn't real, get over yourself.