The Thrawn Trilogy had to be, if not my favorite, one of my favorite series of all the Star Wars books. And I've read a LOT of them. Whole bookshelf dedicated to them. 
Edit: I forgot to answer the question. I think Thrawn is a cool character. Chiss are awesome, and specifically he is created very well by Timothy Zahn in those books. If you get the chance, also read Outbound Flight. It gives more insight on what they are talking about in the Trilogy.

Edit: I forgot to answer the question. I think Thrawn is a cool character. Chiss are awesome, and specifically he is created very well by Timothy Zahn in those books. If you get the chance, also read Outbound Flight. It gives more insight on what they are talking about in the Trilogy.