I can't really attest to the merits of steel versus titanium as I have never rideen a titianium. However, I have always been a fan of steel. Carbon fiber is just a little too flexible for my 210-lb frame. Weight used to be an issue when I was racing back in the 80s and 90s. But now, I am strictly riding for fun. Titanium is way over-priced in my honest opinion, especially when I am no longer racing.
I am not affliated with this business in any way, but you may want to check out this guy.....he has some good deals on frames...and I purchased my Merckx from him a year and a half ago:
http://gvhbikes.com/current.html
I am currently riding a Merckx frame with the Faema paint scheme and an Campy-10 set-up. This is my fourth Merckx. I have a long torso and relatively shorter legs. In the end, frame fit was a more critical factor than weight and stifness. Merckx's Century geometry fit me much better than most other frames I've ridden.