I like Syaoran and Sakura, too. Although, shouldn't there be a pairing listed for Kurogane and Tomoyo, 'cause I'd vote for that, too, if possible.
[kind of a spoiler below...]
About the relationship between Clow and Yuuko
They have been business associates for a considerably long time. They once travelled to Cephiro and met a strange creature that looks cute and delicious. That's what inspired them to create the Mokona twins. CLAMP should keep their old albums online. Those short diaries of the adventures of Mokona Modoki are so much fun to read...
Clow was also supposed to leave the Key of Clow to Yuuko after he dies, but... read XXXHolic.
BTW, about Himawari, Yuuko told Watanuki, from "That girl... she probably won't be your lucky goddess." to "Had you not met that girl, would you encounter that accident?" to "I can see why she's causing so much trouble."
Yet, Yuuko is not telling Watanuki to stop seeing the girl, rather, she is encouraging him, "you're a guy, right? Show her what you got!" Maybe Himawari has some sort of dark power that is causing bad things to happen. She does have something to do with the monkey hand...