My favorite bands are definitely SHINee, Exo, 2ne1, BigBang, and Epik High. I also really like CNBLue and FT Island. And Block B. If we're talking korean indie, which I also love, it must be Glen Check, Nell, 10cm, Urban Zakapa and Lim Kim. In artists, I love Lee Hi very much. I also like Ailee and IU~ I have a lot of favorite voices in kpop, but my favorite ones are definitely Kyungsoo, Jonghyun, Hongki, Onew, Minzy, Taemin, and Lee Hi. I ccould just get lost in their voices.
I used to like 2NE1 and SHINee...and a lot more but those were my favorites. I don't listen to Kpop anymore, it has become so superficial and unrealistic for my taste. :/
B1A4, 2PM, 2AM, Nu'est, Infinite, SUJU, F(x), Orange Caramel, G.O.D, Yim Jaebeum, Lee Seungchul, Kim Bum Soo, Tim Hwang, Son Ho Young, Sung Si Kyung, Ali, ERU, Shin Hyesung, Kim Jaejoong, DBSK (old with all five), Lee Seung Gi, Jang Yoon Jeong, Jeong Dong Ha (Boohwal), Ha Dongkyun, Hong Kyungmin, EXO, V.O.S, Cho Janghyuk, Wheesung, Sweet Sorrow, Youme, K.Will, F.T Island, C.N Blue, Kim Jinho, SGWannabe, Tei, ....
bigbang, exo, 2ne1, AKMU, team B and Winner
mine change all the time but right now my favorites are BTS, Kim Jaejoong, MBLAQ, Zion.T and Bumkey.
Gosh, I have that many bands/artists that I love because of liking kpop so long. I'll try to keep it small and go for the ones I follow more often. I'll put solos down for some, even though they where/are in established bands, because technically, they've gone solo. They're a new artist I would say!

2PM, 9Muses, 100%, AA (Double A), A-JAX, APINK, B1A4, B.A.P, BEAST (B2ST), Bigstar, Boyfriend, BTOB, C-Clown, CRAZYNO, Cross Gene, D-Unit, f(x), F.CUZ, G.NA, History, Heo Young Saeng (Solo), Jo Kwon (Solo), Infinite, Kim Hyung Joong (Solo), Kim Hyung Jun (Solo), LED Apple (if you consider them kpop), MBLAQ, Miss A, MR.MR., MYNAME, N-Sonic, NU'EST, Park Jung Min (ROMEO, Solo), Phantom, RaNia, Roh Hi Hoon, SHINee, Spica, Sunmi (Solo) Super Junior, Tasty, Teen Top, TOUCH, Trouble Maker, U-KISS, VIXX, Wonderboyz, ZE:A

Wow, my shortening it down it still doesn't look very small...and I could add more. xp

Yeah, I will forever be excited because of SHINee the most despite all of them! But if any of the others went "oh lookie here, we have a comeback soon" I would run to see what was happening almost as much!

[I was going to put Supernova (Choshinsung) down, but whilst they're a Korean made band, they tend to promote more in Japan so I wasn't sure, so I'm putting them here anyway.]
EXO, SHINee, TEENTOP, Infinite, NU'EST, U-kiss, AKMU and 2ne1
TVXQ, Infinite, BtoB, B.A.P, VIXX, and lately I've really liked a new group named LEGEND (Their debut song "Left Out" is daebak!!!)
EXO, SHINee, B.A.P, Big Bang, T.O.P, MBlaQ, 2ne1, T-ara, Sistar, AKMU, ...
SHINee , f (x) , infinite, boyfriend,  teen top ,b.i.g , b.a.p , girl's generation , exo, cnblue , vixx , ze:a , ss501...
Fve-Dolls ,The SeeYa, Yangpa, Davichi, Orange Caramel , Fx , Sistar , Beast,  SNSD , Henry ...
It's not that I hate girl groups, I have some that I like but I like guy groups more. 
EXO, BTS, VIXX SHINee, U-Kiss, BIG BANG, BEAST, MyName, B.A.P, Block B, Infinite, B1A4, GOT7, AJAX, TVXQ, SuJu and some more.....
2NE1, F(x), Miss A, Girl's Day, Girls Generation, A-Pink...
Ailee, IU, Jay Park, Gray, Kim Hyun Joong (SS501)... I can't think of any more right now~ 
2NE1, Bigbang, LYn, Baek Ji Young, Taeyeon, Brown Eyed Soul
INFINITE 
BTS
B2ST
VIXX
Always: DB5K and Shinhwa