I've tried just about all of the different flatwound strings over the years and my favorites are Labella (the ones that are .049-.109) and Sadowsky. Labella has the real old-school sound for R&B and Blues, the most punch, decay, and not a lot of high end, relatively speaking. The Sadowskys are a little brighter, smoother and more sustaining, but they are still somewhat in the old-school catagory.
I've used Chromes but I find them to be too bright and hard-edged sounding. I don't like the feel of these as much either, they feel stiff. Thomastik's TI flats are an interesting string, but totally different than old-school Labellas. The only bass I really liked them on was a fretless. They are just too light in tension for me to be able to dig in and play the way I want to. Also, they have more of a mid-heavy sustaining sound, and not as much "bump" up front.
I know many players like the newer flats like Chromes and TIs, but to me they're sort of a different animal than "regular" flats. Just my opinion so hold the hate mail.

Other flats that I consider to be "regular" are Fender, Rotosound, and Ernie Ball
Currently I've got Sadowskys on my Fender American Standard Jazz Bass, and LaBellas on my old Tokai Hardpuncher P-Bass. I love them both! The Jazz w/Sadowskys is easier to play and more versatile. The Tokai w/Labellas is the total Jamerson sound, not as versatile, but funky!