Road Cycling - Eros

I am going to buy a new bike soon. I've been riding a kona lavadome for a year and although I've tried, I never could love the bike. It looks good but never felt good.
My choice is the Bianchi Eros. I have one little question though. Bianchi bikes come in 49, 51, 53, 55, 57 etc. sizes.
I have a 32.5" inseam, which should give me a 55cm frame (given the .67 rule). The standover height is 31.5", which leaves barely one inch between the top tube and the important reproductive things. Is this enough? A 53" frame has a 31" standover height. Which gives me a 1 1/2" space.
Does anyone have an idea how a 2cm smaller frame can have only a 1/2" difference in standover height? And which size would you recommend?
Thanks for the input.
the green lion.

conversions of inches to cm can get a bit confusing, anyhow

I checked your inseam measurement with this;
size calculator (http://www.performancebike.com/shop/sizecharts/roadsize.cfm)

it says that a 55cm would work but again it is all about comfort. I'd say go to your LBS and ask to test ride some bikes, try 52cm to say 58cm and see what works and what doesn't.

Once you got size down then you can figure out the rest ;)

(anyone notice that a lot of people are buying bikes right now? heh) :D

Standover height depends on 2 dimensions
1. Frame size
May be measured from the centre of the bottom bracket to either
a) The centre-line of the top tube
b) The top surface of the top tube

2 Bottom bracket height from the ground.
This also depends on the tyre size.

Most geometry charts tell you both figures.

Sometimes the manufactured product varies from the geometry specs. The only dimensions I trust are the ones I measure myself with a tape measure.

You need adaquate standover clearance, and the modern style is to give you plenty (1-3" for a road bike), but far more important is the length of the bike from saddle to bars.

Eros - The god of love, son of Aphrodite.

The fact that none of us think twice about such a name for a bike should tell you something about the company you're in.

I think that for overall comfort on the bike, top tube length is even more important than standover height. It will be hard to guage what is right if you don't have past road-bike experience (lava-dome sounds like a Mtn. bike, to me), but give it some thought and discuss it with the salesperson. The standard rule of thumb is that, with your hands in the drops, the intersection of the stem and h'bars should obscure the front hub. That's just a starting point, maybe somebody else here can provide a better guage.

As a point of reference, my '93 Bianchi has a longish top tube. Don't know if they're still put together that way. In general, the Eros strikes me as a very good choice for an all purpose road bike.