They make 1" threadless headsets still... lots of choices on the big sites and an LBS should be able to order something basic or beyond. A threadless setup should be stronger and stiffer since the steerer doesn't have to be 22.2mm on the inside and threaded on the outside. I find they tend to hold adjustment better than threaded headsets too and are far easier to set up than a threaded headset, you don't need many tools to adjust it. There's also a wider range of threadless stems available these days. About the only disadvantage is that once you trim the steerer tube you're kind of stuck with a limited height adjustment with your stem but you can buy stems with more rise and/or re-arrange spacers to tweak the setup. Some folks will install a whack of spacers and ride for a while before trimming the steerer tube. This topic gets beaten to death often around here so you can search the archives for more information if you want.