It's nice to see that you're also into Japanese music! =)
Since you're a musician, I would recommend Ikimonogakari. I'm not sure about how well known they are overseas, but I'm sure you have at least heard of them. lol
Their new releases are somewhat famous, so I'd recommend listening to their older releases. Their debut album (桜咲く街物語, Sakura Saku Machi Monogatari, SSMN) is still my favorite album of theirs.
I'll leave some of my favorite songs listed below:
Sakura Saku Machi Monogatari:
- ひなげし (Hinageshi);
- ホットミルク (Hot Milk);
- うるわしきひと (Uruwashiki Hito).
- 青春ライン (Seishun Line);
- @miso soup;
- ちこくしちゃうよ (Chikoku Shichau yo);
- 月とあたしと冷蔵庫 (Tsuki to Atashi to Reizouko).
My Song Your Song:
- 気まぐれロマンティック (Kimagure Romantic);
- かげぼうし (Kageboushi);
- くちづけ (Kuchizuke).
- 会いにいくよ (Ai ni Iku yo);
- NEW WORLD MUSIC;
- 愛言葉 (Ai Kotoba);
- おやすみ (Oyasumi).
- ぱぱぱ～や (Papapa~ya);
- マイサンシャインストーリー (My Sunshine Story);
- 東京 (Tokyo);
- ぬくもり (Nukumori);
FUN! FUN! FANFARE:
- Can't choose favorites. Listen to them all. lol
- 無題～遠くへ～ (Mudai ~Tooku e~)
(This is arguably my all-time favorite ballad.)
There you go. If you have the time, though, I'd recommend listening to their complete discography. It's gold.
they've sung songs for anime like Bleach and Naruto so I reckon they're fairly known among overseas anime (particularly Naruto/Bleach) fans