If you want a round one that works with the lock out, I'd say you want a VooDoo, or Team VooDoo. They'r solid milled aluminum and thread on instead of using hceesy set screws. A google search for team voodoo should find you the page.
EDIT: heres a link for ya to make it easy. Just follow the link from this page (that I linked) for prices and applications.
http://www.teamvoodoo.com/Voodoo/Knobs.html
I have a voodoo knob and simply love it. It's got a great feel to it, in fact when I first put it on I'd drive my car just for the way the shifter felt......
