Generally, administration expenses, taxes and general creditors (in that order) get paid before beneficiaries. The Goldmans are general creditors. However, pension plans, retirement accounts and life insurance proceeds are usually exempt from creditors (depending on state laws). Other assets may be exempt as well depending on state law (i.e. homestead and annuities are exempt from creditors in Florida). These exemptions do not apply to the IRS which can attach just about any asset.
Fraudulent transfer laws (depending on state law once again) can apply to transfers to family members for less than fair market value. Generally, the person looking to establish a fraudulent transfer must establish that the transfer was for less than fair market and done with the primary intent to avoid creditors. If successful (can sometimes be difficult to prove intent), the transaction can be reversed. Statute of limitations can be a hurdle if the transfer occurred a long time ago.
One of the interesting things that I saw was that the Executor (OJ's attorney was named his Executor) stated he would make sure the Goldmans would get nothing. The Executor generally owes fiduciary duties to both creditors and beneficiaries and is not allowed to favor one over the other. It would be a breach of fiduciary duty for him to favor the beneficiaries over creditors of the Estate. He has since walked back the statement but you get the idea of where his mind is at.