the ever shifting stable loaded with comfortable road bikes and city and winter bikes
there was a multi part write up of SA touring in recent Adventure Cyclist magazines, starting with the May 2006 edition. become a member of ACA and order some back issues. Torres Del Paine look beautiful.
There are very strong west winds all summer long in Patagonia. I spent a few days in Punta Arenas along the Straight of Magellin. There was nonstop audible wind 24 hours a day. It would drive me insane to live there. Biking from the airport into town was not easy because of the very strong crosswind. It was hard to maintain control of the bike when a truck would pass me when I was returning to the airport, because it would momentarily block the wind.
I toured in northern Patagonia in both Chile & Argentina (the Bariloche area). There was a moderate west wind on the Argentine side, especially when you got further away from the Andes, but it wasn't nearly as bad as the wind in the far south. As you move away from the Andes on the Argentine side, the landscape quickly gets bleak. The Chilean side is green and lush. Other cyclists have raved about the Carretera Austral, the route in Chile south of Puerto Montt.
I have not toured the area but have mountain biked in the Argentinean side of the Andes (Bariloche, San Martin de los Andes, Villa Langostura). This is a common bike touring region in summer. The scenery is very nice and these days food and lodging in Argentina are dirt cheap, specially if you are coming from the EU. The best months to tour the area are December, January and February. A real touring bike would not work for you. You would need a mountainbike, either rigid or hardtail. Also plan to take some outer shell for the evenings as temperatures drop at night. I've never been to the Chilean side but you probably want to go there also during the summer months. If you decide on the Argentinean side you should fly to Buenos Aires and from there to Bariloche or San Martin de los Andes.