I like Roddick's serve! It's just different, but I like it a lot. I think the original poster is the only one that finds Coria's serve ugly, it's not very effective but it's a very very nice motion IMO.
I can't stand Gaudio and Ljubicic's serves. They're SO ugly it should be banned.
Davenport has a nice motion similar to Hingis, but she has a ******** smile before she serves, just ruins it completely.
Nadal doesn't do well on the clock because he's not a natural lefty, I'd like to see you all try to serve with your non-dominant hand... it's HARD. However, he places and spins it very well which makes it just as good as many player's serves. Also one factor is intimidation. Nadal's speed puts a lot of pressure on his opponents. They know that even an attack of perfection will probably be tracked down by Nadal's speed. If they don't attack perfectly, Nadal's groundstrokes will eat them for dinner, so there's really humoungous pressure on the returner.