I agree with Boanerges, above. I think the Old Testament standard is a kind of starting place, a guide as to what we ought to be able to give.

But just as the Lord Jesus "toughened" the Law from killing a man to hating your brother and from adultery to looking at a woman with lust, I feel the same way about the giving standard - from 10% to giving sacrificially from the heart!

Sacrificial giving may be more or less than 10% I suppose, but for most people, 10% is hardly a sacrifice.