I'd go with heavier than 1/2" if you can afford it, easier on the hands and a lot of benefit in terms of max breaking strength. To me three strand is preferrable as it is likely to be half the price of braided and much easier to splice. Look for the softest three strand line you can find, what they are selling at W.M. now gets very stiff quite quickly. Snubbers help limit the strain on your anti-chafe gear on the bow and stern and in my view are mandatory on a boat 35' and up, although with my 24' and 27' boats previous to the one I'm on now I never used them. Braided line will stretch less so if you plan to dock your boat and walk away from it for a month or two there may be an advantage there. You could easily befriend someone at the marina however and causually ask that they keep an eye on your boat and tighten up your dock lines as needed. DrB has good advice and I would plan on bowlines, stern, and fore and aft spring lines on both sides of your vessel.
Many folks in my marina use dedicated lines that they fasten permanently to the dock for mooring at home and keep another set of mooring lines either on the bow and stern or in a locker for use visiting other locales. This has the advantage of limiting wear on the lines you are likely to be heaving to a stranger fighting a tide to get into a tight slip or mooring, although it may be something to persue after you have already worn out your first set of docklines and wish to reuse the shorter remnants you now have available.
Sailing a '74 Challenger 40' Ketch rig out of San Francisco
Last edited by sfchallenger; 05-17-2011 at 11:38 PM.