Originally Posted by halfspeed
There's no point in going to threadless. Threadless was invented to make things more convenient for manufacturers. It just so happens to be marginally lighter and stiffer as well. On the other hand, unless you've got a lot of uncut steerer, threadless gives you a lot less height adjustment. On the gripping hand, you only need an allen wrench to adjust the bearing preload.
All in all, it's a bunch of minor differences that usually don't justify the expense to "upgrade" in either direction.
In fact, most of the differences that get hotly debated here are trivial and most of the "facts" used in the arguments are suspect at best.
While I wouldn't go to a threadless fork unless the original fork is jones, the threadless adapter makes sense if you are in need of adjusting the reach or height of the stem. Looking at the stem that is on the bike, it's rather high. The threadless adapter lets you experiment with lots of stems in various reaches and angles. And, let's face it, there are far more stems available in 1 1/8" then there are quill stems available. And the fact that most of them have two bolt face plates makes them easy to change.
Get one and experiment (keep the threaded fork, however...for now
).