For sport (and indoor wall climbing) a 'single' rope should be used, ie one that has passed its single rope test.
In the early days of sport climbing, pitches were seldom as high as 30m, so a 60m rope was generally long enough to allow one to climb the pitch and be lowered off back to the ground in safety. Nowadays, many pitches are longer and ropes of 70m and 80m are the norm. Needless to say it is crucial to check the length of a climb and make sure that your rope is long enough before starting it; as a safety measure the belayer should always tie in as well.
For climbing walls, a much shorter length will be needed - check the height of the wall, double it and add a couple of metres for tying in.
In terms of wear and tear, a thicker rope with a thicker sheath will last longer than a lighter one, but will be heavier so can create serious rope drag on a long hard pitch. This can be mitigated to some extent by using extended quickdraws and even specialist karabiners like the DMM Revolver, but for those seriously pushing their grades, a lighter albeit less hard wearing rope is the solution.
Dry treatment is generally not really necessary for sport climbing ropes though it may be desirable if you intend to use the same rope for other applications such as crossing a glacier to get to a climb. It also helps the rope wear better.
This page shows only ropes suitable for sport climbing, for our full range please see our Climbing Ropes and Abseil & Safety Ropes pages. For more information about ropes in general please see our Climbing Ropes Information page.