My favorite actors include those who sing for the themes in the show (Minami Kuribayashi, Yui Horie), those skilled in delivering anger using a coarse voice (Yumiko Kobayashi, Satsuki Yukino) and those with very versatile and variable voices* (Yuji Ueda, Megumi Hayashibara).
My opinions on English voice actors are inconclusive as of yet.
If you want to see the name of a voice actor for a particular character, search the databases of Anime NFO (
http://www.animenfo.net) or the Internet Movie Database (
http://www.imdb.com). You can search by show or character.
* I could not recognize Yuji Ueda's voice in the 11 shows I've seen him perform in after my first (which escapes me at the moment). I also sometimes confuse Rie Tanaka and Satsuki Yukino. I don't know if being unable to quickly recognize a seiyuu by performance multiple times is a proper way to identify good voice acting.