I read both Rosario + Vampire 1 and Season 2. R+V 2 manga is far better than R+V 1. However, you should read R+V 1 first.
I tried to remember more comedy and romance manga.
Ai Yori Aoshi
Ah! My Goddess! (aka Oh! My Goddess!)
Airgear
Ayu Mayu
Bamboo Blade
Change 123
Girl Saurus and Girl Saurus DX
My Barbaric Girlfriend (aka Your and My Secret)
I"s (I like artwork, but plot was not great)
Kaichou wa Maid-sama!
Special A
Kodomo no Jikan
Hatsukoi Limited
Ai Kora (aka Love & College)
Magikano
Mysterious Girlfriend X
Nagasarete Airantou
Pastel
Rappi Rangai
REC
Sekirei (also twin sisters)
Seto no Hanayome (aka My Bride is a Mermaid)
Skip Beat!
Tenjou Tenge
Tona-gura
To-LoveRu Trouble
Umi no Misaki
Umisho
ToraDora!
Zero no Tsukaima (aka The Familiar of Zero)
One Pound Gospel
Lovely Complex (aka Love.Com)
Gacha Gacha (also Gacha Gacha The Next Revolution)
Boys Be…
Nodame Cantabile
Perfect Girl Evolution (aka The Wallflower)
Girls Bravo
Fruits Basket