i've got the 3.73s, they suck in city traffic, you have to take turns in 3rd unless you want to be really loud, while you're shifting into 3rd everyone around you will be in 2nd and have more power. the longer 1st gear that 3.55 (or even better 3.27) offer will also give you more time to evaluate if the guy next to you wants to race, if so you can stay in first, if not shift. it sucks shifting to 2nd then finding out the guy next to you is racing. that said, of course the higher(numerically) gears will be faster and if there is no traffic in your area, go big, otherwise 3.27s are great.
i copied this from my response to a similar question from another forum because it is even more applicable here.