Wow, you guys read so little Ecchi. It's saddening. U_U
Ecchiest manga for me, well, the list is too long but let me remember.
Nozoki Ana - the best that I've read. It's strongest point is its character and their personality depiction. Hell, even the great mangas can't present the psychology of characters as well. It's ecchi stuffs also are really on the borderline - more of a smut.
Aki Sora - The most profound incest ecchi story I've read. Sure, the harem parts is at times sickening but if you are looking for real ecchi, you shouldn't miss that.
Kiss x Sis - This is the most funny take on incest I've seen perhaps. It's scene are pretty much smut too but for its hilarity and the way, it doesn't get way too harem, it's definitely one of the best.
To LOVE-Ru Darkness - Lots of great looking girls, great harem part, a pretty good storyline, very good *** scenes - what's more to ask? In fact, you can also check the first one 'To Love-Ru'; then see this sequel. That'll make up for your good dose of ecchiness.
I Fell In Love For The First Time - This is a very short manga (4 chapter) but I love the way they presented a sweet Yuri story. It's a sincere take and definitely worth a shot.
Uwakoi - From Aki Sora's creator, this one has just started but is equally as promising as its predecessor. In fact, the designs of characters is closely similar.
Yuria 100 Shiki - A cute robot girl that's meant to become someone's slave forever but wants to find true love. Add to that lots of ecchi stuffs, some other great looking girls, funny ecchi talks and the mix is great entertaining ecchi manga.
Virgin na Kankei - I won't say much on this one. Simply it's a great ecchi manga since it has all required elements - a decent love story, great looking girls, lots of explicit ecchi stuffs and even a sequel that follows.
Teacher's Pet - This one is based on an interesting blackmail story and even rape that'll turn into a love story. It's the story of a teacher who is married with the Principal and gets raped by a student who turns out to be the Principal's brother. How the small brother blackmails the poor teacher is quite interesting. Too bad, it's a short manga but it makes up for a good read cause the storyline is not so weak. There's a sequel which is also short.
Self - This one has not much chapters and is supposedly ongoing but it has a pretty different storyline. It's about a guy who never masturbated in his whole life and is now questioning his own inner self. No, it's not Yaoi stuff.
Mama wa Doukyuusei - A guy discovers that his new step-mother is actually his classmate. It perhaps does not has much *** but there's lots of ecchi stuffs and nudity. Also, the story is not a weak one; so it makes up for a very good read.
GTO Shounen 14 Days - Well, fans of Professor Onizuka, rejoice. This one is long spin-off of GTO and well, in more ecchi than ever, this one is one brilliant ecchi manga.
Well, these are 12 very good ecchi manga. There are like so much more that I've read but this is a good list. I can add more later on. There are so many great ones...
EDIT: I watch rarely the ecchi animes (besides some like Kiss x Sis OVA and some more). I prefer reading ecchi and watch hentai.
