Memory might be my favorite as well! Not sure yet, I haven't finished the series yet...I'm mostly through Diplomatic Immunity, was planning on posting when I was done but then kept getting distracted and haven't finished it yet.

Illyan & Alys are darling (most especially for Ivan's reaction to it, HAW, oh Ivan!) And A Civil Campaign was amaaaaazing (omg the dinner party scene, howling out loud! yay for the butter bugs!) I might love this series most for its humor...it's so unusual in the hard scifi genre, but it works so well, makes the characters so human and lovable for it...

(and hi, welcome! There will be more Thaw soon, possibly tomorrow if I get on the writing ball now - so glad someone's interested! ^^)