First time poster, long time lurker, so I figure I should contribute something. I will be an owner of a 2SSM6 sometime within the next week to 2 months. For now I drive a Honda Accord... 168HP...white... with beige interior.:(
Anyway, part of my decision as to which trim to go for was the plusses and minuses of the V6 vs the V8. I used a spreadsheet to calculate gas cost for each.
Since everyone seems to have their panties in a bunch over the rising price of gas, I wanted to show that its really no big deal and
you should not use rising gas prices as a reason to 'settle' for the V6.
Ok, here's the math...
I start with the EPA ratings then reduce them to more realistic levels with modifiers based on city driving and 'lead footyness'. 18/29 EPA for V6 manual and 16/24 EPA for the SS manual.
My inputs:
------------
gas 87...........$ 2.80
gas 93...........$ 3.05
city mod........50.0%
leadfoot mod..50.0%
miles / yr......12,000
50% city means I drive half the time in the city. 50% lead foot means I drive agressively half the time and baby it the rest. The V8 gets premium 93 octane, the V6 gets 87. The results of the above inputs are:
Cost
MPG Gallons Yearly Monthly Daily
V6 18.8 640 1,792.00 149.33 4.91
V8 16.0 750 2,287.50 190.63 6.27
-----------------------
495.50 41.29 1.36
=> V8 costs 27.7% more
So there will be a 27.7% increase or $1.36 per day cost from choosing the V8. Now lets consider if the price of gas shoots up to what it was a couple of years back at $4.50 a gallon (this seems to be scaring everyone the most):
gas 87.............$ 4.50
gas 93.............$ 4.75
City mod..........50.0%
lead foot mod...50.0%
miles / yr........12,000
Cost
MPG Gallons Yearly Monthly Daily
V6 18.8 640 2,880.00 240.00 7.89
V8 16.0 750 3,562.50 296.88 9.76
------------------------
682.50 56.88 1.87
=> V8 costs 23.7% more
As you can see... the pricier gas lowers the difference between the V6 and V8 (27.7 drops to 23.7% increase). So contrary to what you would expect, if you think the the price of gas will go up in the coming years, voodoo logic says you must get the V8 !!

Provided your driving habits don't change, the difference between $2.80 gas and $4.50 gas:
V6: $1,088 more per year ($2.98 a day)
V8: $1,275 more per year ($3.49 a day)
You can make this money up in many ways...quit smoking, go out to dinner one less time a week, etc. Bottom line; don't panic over $4.50 gas.
There are many valid reasons to get the V6 over the V8 (purchase price, 20" tires, insurance, etc), but please don't let the price of gas nor the thirstyness of the V8 influence that decision.
Cheers