Serac said:
Semi-slicks. I think the loose stuff around here lends itself to a slightly more aggressive tire. For me, small knobs and round profiles are great. More traction with these means (I think) more speed. I just run slightly high pressure (40-45 psi).
I guess what I am really wondering is if what works in a tubed system can also work in tubeless or does one tend to run lower pressure after stans and, thus, alters the choice of tread pattern?
With Stans, you should be able to convert any tubed setup to tubeless. Note: "should." People have had problems getting the setup to work properly. It takes some patience and an air compressor.
I wouldn't go much higher than 40psi using Stan's with standard tires. I typically run around 35psi (ran around 40psi with tubes) and have no complaints. The beauty of tubeless is that you don't have to run higher pressures to avoid flats. If you do want to run higher pressures, you should get UST tires and run some sealant in them. You'd probably end up dropping 5-10psi after the conversion anyway.
One of the reasons for avoiding higher pressures with Stans is that standard tires are lighter, but their sidewalls and beads are designed to be supported by a tube. Standard beads (and standard rims for that matter) tend to vary from brand to brand, and if you combine brand x rim with brand y tire using Stans, you could get the bead to blow off the rim at higher pressures. Some of the newer Bontrager and Nokian (I think) standard tires are coming with UST beads mated to a regular carcass. They're susposed to be used with UST rims and sealant. Nice solution. You get a great bead seal and a lighter tire.
Anyway, you'll hear all kinds of pros and cons, especially about Stans system. I love tubeless and won't be going back to tubes anytime soon. I'm compromising with regular tires and UST rims (XM819s). My ride feels faster and has more traction, even though I'm running lower pressures. And, oh yeah, haven't had a flat in about 2.5 years now

I'd rather ride than fix a flat any day.