whether it is acceptable or not is totally depend on u.. if u think that speed is enuff for u, and most importantly stable for ur 24/7 usage, then okeylah .. just make sure that absolute max vtt for 45nm quad is 1.45v when ur vcore is 1.45v. else u risk killing ur proc 

try increase ur vtt a lil bit.. to let say 1.3..

You can use some software to get lower vcore than Auto/stock..... 

act no.. auto is not the lowest.. some board tend to increase the vcore automatically up till 1.4vcore when we leave the setting at auto..
huhu try realtemp and see what's the temp
btw i just manage to test 3 coolers for my x3350.. geminII, ocz vendetta 2 (/ xigmatek s1283) and intel stock cooler 

and yes, geminII is the best among these 3 coolers..

Normal.Your HSF should feel warm,not hot during load right?Normal if like that

I used the same hsf as your, that Noctua cooler on my QX9650 for 1 month.. Yea, it seems that noctua cannot tame the penryn procs. So, yesterday i change to TRUE 120, not much different but i'm quite happy with 49c (core temp) or 39c real temp on idle and 57/47c on load. but i notice that pairing noctua with my e6600 es proc is almost like marriage made in heaven. Nver exceed 20c, the lowest is around 9c and average 17C. Yesterday, i put another fan to the noctua and bios showed the temp was -2C   Unfortunately, BSOD after that coz i made a drastic increase in frequency when did the OC, mayb today try again after reset the CMOS.