I wish shoes were easier to pick!

Did you take your old pair of shoes in to the store? Did they actually measure your feet and evaluate your stride running (like on a treadmill?) and did you have a chance to give the proposed shoes a go on the treadmill at the store?  If they didn't do or offer those things when they offered you the shoes--you may want to try a different store.  If, in trying on all the shoes, there really is nothing to distinguish them apart to make them different for you, then go onto RunnersWorld.com and see if your shoes are in their shoe ratings at all.  Check out the gear reviews here as well and see if any of the shoes are listed.

If still there is nothing, pick the ones that go with your running outfits best.  One thing I did when I had two I couldn't decide between was I bought both pairs...alternating shoes helps extend their lifetime and reduce chance for injury for you due to the fact that the shoes get to "recover" more as well.  While doing that, I found that I liked shoe a. over shoe b. so when it was time to buy the next pair, I bought the pair the model that worked best of those two.

X2 

X3.  I have found this is really the only sure method.  You won't really figure out if a shoe is right for you until you've done a couple 8-10 mile runs in them.  Just keep trying them and you'll come across a pair you love.  A little expensive at first, but worth it in the long run.

I just experimented with some New Balance 768's.  They felt completely awesome in the store, but after my first 8 mile run they were retired - just not enough cushioning for my flat feet under a 205# body.  They are my new upper body/core workout shoes now.     Back to my Saucony Grid Propels...