Hi, and welcome to FlyerTalk!

Along with the opinions you get on this thread, you might want to check out these threads in the Hong Kong forum:

http://www.flyertalk.com/forum/showthread.php?t=426735
http://www.flyertalk.com/forum/showthread.php?t=449157
http://www.flyertalk.com/forum/showthread.php?t=539578

I can tell you that HK immigration is usually quite efficient. And if you've never been, I really must recommend at least going to view the skyline. It is perhaps the most beautiful and stunning in the world. Then grab a decent night's sleep somewhere. Priceline might be a good bet for a hotel. Have a good trip!