miyuki sawashiro, hands down. i think i first heard her as celty in drrr but she won me over immediately when she voiced franziska von karma in the aai trailer AND HAS SINCE THEN BECOME QUEEN. when you voice the character i soulbond over, i soulbond 2 u. and i love way too many of her roles since then, though i often gravitate to her sexy onee-san ones cause that's generally my type

runner up though is definitely saori hayami who i've grown to love since oreimo. she's risen quite a fair bit and I HAVE A SOFT SPOT FOR HER. she does the haughty tsundere type well and i will always root for her should she voice a girl in a harem

HAHA man i know i've written this answer before but i have many favorite seiyuus in general though. i can't watch an anime without pausing and being like I KNOW THAT VOICE... WHO IS THAT VOICE!??? so i also want to shout out aki toyosaki, kanae ito, yukana, fukuyama jun (mainly because he's such a loveable ham), nobuhiko okamato, hosoya yoshimasa, kamiya hiroshi, kousuke toriumi... my top 10

edit: also i've been playing tokimeki a lot recently and that game features a lot of everyone's favorite seiyuus (suzimura, ishida, nakai, junichi, etc...) what's great for me is that i have a one syllable name in real life so i can make them actually pronounce my real name AND IT'S SO FUN, IT ACTUALLY FEELS LIKE THEY'RE CALLING OUT TO ME. it is truly the greatest piece of seiyuu fanservice to exist