I really like how the Rapidash, Entei, and Lugia look, they are very cleanly fused.
The biggest advice I can give to you is save them as .png, not as .bmp, .jpg, or whatever. .png gives sprites a nice clean look to it.
Awww maaaan...that's what I was gonna' say
But I want to say that I particularly like the Lugia one.