I love the soft chromaticism of No. 10. Maybe it's just me, because this sonata isn't talked about as much. No. 5 is a close tie. I also really like 4, 7, and 8. I don't really know why I can't enjoy early Scriabin as much, as I feel like there were many similar pieces that I can enjoy more by contemporaries. However, late Scriabin is much more unique and hard to come by in much other pieces.