Contemporary forks require new standards in frames. Thankfully the industry settled on the 1 1/8" to 1 1/2" tapered steerer standard that is pretty much universal among all manufacturers (except Canondale, and who really cares about them?). To meet this standard tubing manufactures have provided three options that work really well and look pretty good.
Again, this particular HT is kind of a hybrid as it can easily run both a tapered or a straight steerer tube. That said, its true intended purpose is for tapered steerers. It gives the builder an easy to miter, economical option. For the HT to be compatible with tapered steerers you will need to run a 44mm external headset for the lower cups and an 44mm inset headset for the upper
This particular HT comes in two different flavors, one that is thinner walled and intended for road or cyclocross bikes. This one requires use of HT rings at the top and bottom to strengthen it up a little bit for all but the smallest of riders. The second version is thicker walled and intended more for either bigger riders or for mountain bike use. This version also has HT rings but are only needed for heavier duty use.
Personally this HT is my favorite of the three. It is far more proportional in size and does not dwarf the other tubes in diameter. Also the use of headset cups gives a better connection to the frame than having the bearing in direct contact with the HT.
Probably the sleekest and definitely the most integrated HT of all three, the Columbus tapered is also the biggest which means with smaller tubed bikes it can look un-proportionally big. However when running the mega tubes from Columbus or S3 tubes from True Temper it fits right in. The biggest downside to this HT is its integrated approach to bearings. While not the biggest problem it does limit you to two types of bearings, one from FSA and another from Columbus (no King headsets for this baby!).
There are a couple of other HT's out there, however these three are the easiest to source, work with, and not crazy heavy. The only notable exception that I did not include is the Paragon Machine Works HT. It is a beautifully machined HT that looks great, unfortunately it is also incredibly heavy when compared to the True Temper 46.4mm HT.