Ti is still around and a great choice if you want a lifetime frame. I've got a ti and a steel Eddy Merckx, both with in the same size and geometry and nearly identical components. They handle the same but the ti frame rides smoother and is my choice for long rides. It is perhaps 1 lb. lighter than the steel frame. The main advantages to ti frames, in my book, are that they won't rust and you don't have to worry about scratching or chipping the paint. Of course, you can always paint a ti frame but that sort of defeats some of its key advantages. Part of the reason why ti frames are lighter is because you don't have to paint them, and paint adds weight to frame. I generally take my ti bike when traveling because it is so easy to scratch and chip paint when loading and unloading bikes.

If I were going to invest all the money it takes to buy a custom frame these days, I would seriously consider ti. Assuming that you have your size and geometry needs dialed in, a ti frame should last your lifetime.