Well I completely ignored the resounding advice of all of you, not on purpose albeit, but I did. I asked Meg what she thought and she said if I wasnt saying that I ABSOLUTELY needed it, then I likely didnt.
Coupled with being cheap, impatient and and early sleeper/riser by the time I was ready for bed I just ordered the 1/2" stuff .Based on the fact that I have dropped in the past, some of the biggest logs/branches/leads I ever have, on old 3 strand and a retired rock climbing rope I used for rigging I am guessing the 10,000lbs 1/2" will be enough.
This way I guess I can still get a 5/8's line at a later date for when I need a big gun and have a real separation between purposes and lines.
Thanks everyone for chiming in, I wish i had waited a bit because in truthfulness I likely would have bought the 9/16's after reading your thoughts, but I guess I have to stick with my rationalization featured above!
Nick