Are there any professional Combobox controls (dropdown list with autosuggestion) based on the jQuery library?
It should be able to handle large datasets and have some skinning options. A multi-column result list would be great too. I’m working with ASP.NET, but it’s a not a problem if I had to write a wrapper for it.

I’m already using a third-party control, but I ran into some compatibilty issues between two vendor’s controls. Well, I want to get rid of this kind of dependencies.
Unfortunately, the best thing I have seen is the jquery.combobox, but it doesn’t really look like something I’d really want to use in my web applications. I think there are some usability issues with this control, but as a user I don’t think I’d know to start typing for the dropdownlist to turn into a textbox.
I much prefer the Combo Dropdown Box, but it still has some features that I’d want and it’s still in alpha. The only think I don’t like about this other than its being alpha… is that once I type in the combobox, the original dropdownlist items disappear. However, maybe there is a setting for this… or maybe it could be added fairly easily.
Those are the only two options that I know of. Good luck in your search. I’d love to hear if you find one or if the second option works out for you.