I buy a lot of both graded and ungraded. I buy the ungraded only because I have 4-5 unfinished sets I am working on. Once the current sets I am working on are finished, I will mostly buy graded, unless I get ungraded coins at a bargain.
I am finding that with the price of silver rising, the price difference between graded and ungraded is minimal. I'll give you some examples. I bought 4 1995 PCGS MS69 graded coins for $95.00. That's about 3-4 dollars more per coin than out of the tube unc. coins. I have been buying MS69 NGC Slabbed Silver Eagles (non-low mint) for $26-$32 for a while.