Probably something like this
-Muramasa
First by a wide margin, I pretty much loved everything about it to death. The writing is fucking great, the cast is amazing, it has a lot of style and a lot of substance, at times I was amazed by all the awesomeness that was happenig, at other times I laughed hard.
And it's never cheap nor too heavy, it's just amazing.
For the others it's a bit hard to rank them, a top 10 would probably be easier for me, anyways:
2nd: Oretsuba
Best cast in eroge + great writing + awesome humor that doesn't go for paper toiler shit or simple parody but is actually witty.
And the plot is actually pretty good as well.
3- Ayakashibito
Kind of similar to Muramasa, though on the lighter side.
Lots of badass shit + some great humor and dialogues with some awesome characters and a pretty good story.
4-Subarashiki Hibi
It has an awesome presentation, with an amazing soundtrack, some pretty good writing and a very intriguing and interesting story.
The big twist was too obvious, the author was a bit too heavy on the references and quotes to push his themes and it felt a bit cheap at times but it's still an awesome experience.
5-Swan Song
I still have shivers when I remember the normal ending.
Others that could make the top include Himawari for Aqua's story, Forest for having Reepicheep from Narnia being an awesome badass, Muv-Luv Alt for the fucking epic second half, Ikusa Megami Zero for Haisherra and G-senjou no Maou because I love mind games and detective story, also the true end was beautiful.
And that's it for my shitty opinion.