How to pick a dress size?

I'm having trouble determining what size to make for a dress (Simplicity 3867).  I took my body measurements and if I go w/ my bust measurement, I'd have to make a size 12 or 14.  But, on the envelope, there's also a set of final garment measurements that would indicate a size 8 if based on my bust size.  What do I use? 

Go by your measurements, not the size on the envelope or what you wear in RTW (ready to wear) garments. And I highly recommend making a muslin, at least of the bodice, before cutting into your dress fabric.

I'm just confused because the envelope has two sets of measurements--body and final garment.

I guess I'll make the bodice lining first as a muslin...that should work fine, right?  This is my first time making clothing other than skirts/scarves/easy stuff, so I'm kinda clueless...

The finished garment measurements are always going to be slightly larger than your actual measurements.  If they weren't, you wouldn't be able to move!   The finished garment measurements are just there to give you some idea how the finished garment will fit (e.g. if the finished bust measurement for your size is close to your actual bust measurement, you can tell it will be close-fitting, whereas, if it's much bigger, you can tell it will be loose fitting).  Like flourishes said, it's a good idea to use the measurements chart to pick your size and make a muslin first to fine-tune the fit. 

Look at what the cutting guideline measurements are, figure out what size from there and then measure those specific pieces on the pattern to see how they compare. Remember that you're going to have to take into account ease and seam allowances, so they should be bigger than your actual measurements but not excessively bigger.

Trace them onto Pattern Ease or even tissue paper instead of cutting up your pattern, then use those for making your muslin. It's a little extra effort but so much better than sewing a garment that's not going to fit.

Thanks for the tips!  I'll have to give the muslin a shot...although that kind of sucks for me since I need this dress ready to go by Friday morning (afternoon graduation dress  ).

I wonder how much ease in the bust area is "too much ease".  I don't want to be flashing the world now, do I?   It looks like this pattern has about 3.5" ease built into the bust...is that loose fitting or tight fitting?

When I measure the pattern to double check, should I just be checking across the bust area and the waist? 

Over at sewing pattern review there are 30 reviews of this pattern......it's obviously very popular.

http://sewing.patternreview.com/cgi-bin/search.pl?CompanyID=45&search=search&PatternNumber=3867

You may find some tips on fitting and sewing the pattern from people who have made it.

Hope this helps.