I have several clip knives, but my favorite is definitely the Smith and Wesson Assisted Opening SWAT Medium, partially serrated. It stays sharp, opens fast, and the serrated blade is great for cutting rope and such in a hurry. I also have a S&W border guard (about ten inches long when open), but it is too big for EDC. A gerber mini paraframe rounds out the collection, and is great for small jobs.
My brothers have Gerber or CRKT clip knives, and overall I prefer my S&W. The CRKT flexes a lot when in use, where the S&W is rock solid, even when abused a bit.
Just my 2 cents.