Definitely
Orange Range - Ikenai Taiyou and
GReeeeN - Ai Uta. These two songs epitomize summer best to me; Ikenai Taiyou is like the fun, let's-go-to-the-beach! song, and Ai Uta is like a summer romance that develops into something more song
I also like Miyavi's "Sakihokoru Hana no You Ni -Neo Visualizm-" a lot; it's a youthful anthem~ I like that it came out in the summer, but for some reason it holds a more spring feel for me. Ai Otsuka's "HEART" also has a nice summer feeling to it
