I'd like to claim enough exemptions so no more tax is taken out, but I'm pretty sure that is illegal.

I did what you're talking about. It's not illegal. I had already had enough tax withheld from my paycheck to cover my tax liability for the year, and also to meet last year's tax liability. It was getting near the end of the year and I didn't want any more tax withheld and so I went to HR here and asked them what to do. They had me sign another W-4 with a pretty big number of exemptions. (I can't remember the exact number; I think it was either 9 or 11.) Anyway, little or no tax was withheld -- but the key to staying legal is to make sure that at the end of the year, enough tax has in fact been withheld.

--SirTas