Well, I have found a list of what women don't want.  This way you'll know what not to buy.  I believe most women will give you a couple hints.  You can always just listen and figure it out.

I don't know how much you were planning on spending on your lady but the average women thinks you should spend about $215 dollars on a present.  The average man wants to spend about 68$.

Now according to FemalFirst here's what not to buy for your lady.

1. Socks

2.  Bath Salts

3.  Chocolate

4.  Perfume

5.  Money

Now I thought they had something until the list had money.  Nothing wrong with handing your lady some cash so she can buy what she wants.