Arco is brilliant. Gear is super cheap and every second shop is a gear shop (and the others sell either pizza and beer or gelato) - awesome ... the dollar was stronger when we were there but I got a Mammut 60m rope (albeit bottom of the range) for about $120 bucks. Also stocked up on shoes at the la sportiva shop for less than half aussie prices(see Neil's photo above) and got some great Salewa draws for about 15 bucks each.
If you get fancy something different while you're there consider going up the valley for a bit of multi-pitch action - I'll try and dig up some info if you're interested in that sort of thing.