consistent fermenting temps

When the yeast package gives a temp range for fermentation, say 60-75*F, is there a preferred temp to keep on either the higher/lower end of the scale?

I had my ales fermenting in my basement which is usually around 68, but fluctuates in hot afternoons up above 75*. I put my carboys in tubs of water to try to keep the wort at a more consistent temp. Is this overkill? (it seems to work well)

In other words, do I just have to stay in the range and accept the fluctuations, or is it better to stay constant? And then on which end of the range? (provided the recipe does not specify a certain temp) I am suspecting it depends on the type of ale/lager...??

Consistency is important. Lots of people use the water tub method. If the temperature is still too warm, you can circulate frozen water bottles to keep it down. I like to aim for the lower end of a yeast's preferred range, resulting in a cleaner beer.

+1 lower end is better with most yeasts (a few exceptions exist, like saisons), and avoiding fluctuations is just as important.

erock and Chshre both have it spot on in my opinion. Consistency, or as close to steady, is key. I personally prefer to keep it toward the low end but it all depends on what your looking for in your brew. In many cases keeping it on the lower end of the range will help avoid the stronger/estery flavors. Some people look for that in their brew - all depends on what you want. As far as the tub of water method - LOT of people use that. So far I'm blessed, my basement is steady 58-60 degrees, drops to about 55 in the winter.

I usually try to keep the temp as constant as possible. For ales around 68 is great. Mine range from 62-75 but I have never had problems except for once. Butter beer is a bit tought to swallow.

I'm typically on the lower end of the spectrum. My average temp is around 68F for most ales.

i like to ferment 1056 at 62

I've found the best results over the years with ales to keep the fermentation temps below 70 and above 65 throughout the entire process. It seems the batches that went warmer (over 70) had more of the strong flavors that were not intended. I try to stay at 67-68.