How does a credit card avail bal to credit limit affect credit score?

I saw my credit score rise a hundred points since I consolidated my credit card balances through a lower-APR bank loan. I am now looking at having that loan plus credit card balances, and I would like to keep my score up. What is considered to be an acceptable (I don't mean ideal) balance to credit limit ratio for a credit card? I have been told that having a card that is nearly maxed out is a dent on your credit. What is nearly maxed out? What I am calculating will be true for a couple is 25%. I will have have used 75% of the credit limit on a couple of cards. Is this really negative, or acceptable?