Whichever you like the best. I've used Carvin's brand, LaBella Deep Talkin' Bass, and D'Addario Chromes on fretlesses over the years, all with great results. I now use LaBella and Fender nylon tapewounds for my fretless basses and I like those even more.
TI Jazz Flats have this beautiful complex midrange that just sings on a fretless. Don't forget to play around with pickup hight and neck relief. Both have drastic effects on the tone. The flatter the neck the more Mwah. I got to the point with my Sx Jazz (with TI Jazz Flats) that I had to losen the truss rod to get more relief, because the mwah was too much.
