so, when i first started getting in to photography a few months ago, i followed some of the beginner tips from Ken Rockwell. One of them was stepping up my filter size to a common 77mm so i wouldnt have to buy the same filter at multiple sizes. Seemed like a smart, economical idea to me, the one caveat being that i wouldn't be able to use the lens hood (which he recommended not using). well, now i am thinking i should be using the hood more, at least i want to try it for this weekends trip (leaving tonight for Austin TX for a long weekend) and am just taking the d50 with the 18-200vr, and the 50 1.8 for a smaller, lighter and night time shots... i was thinking of going over to B&H today (i have a few hours to do so) and pick up a circular polarizer to stick on the 18-200vr... what do you guys think? is a polarizer filter ok to leave on a lens full time? i anticipate a lot of out door shots and the weather looks good in Austin... or is it just a waste of $65 dollars? any (quick) replies or thoughts greatly appreciated thanks!