I presume you applied any available firmware updates? There was a firmware update some time back which addressed some issues of freezing, though it might not help, or have helped, in your situation.
Freezing coming out of sleep is, in my opinion, unlikely to be a problem with the hard drive, though it's not impossible. Since replacing the drive hasn't helped, a problem with the logic board seems indicated. Problems that happen only to a relatively few systems (and even if there are "hundreds of threads" here about the problem, that's still only a very small fraction of all MacBooks sold) can often be very difficult to diagnose, and for such small numbers the standard repair procedures normally handle it.
If this problem appeared prior to the warranty on your MacBook expiring and Apple was unable to solve the problem, you would have grounds to take this up with Apple Customer Relations and ask for some sort of resolution, perhaps a replacement of the system. You can call the Apple tech support number and ask to speak with a CR representative and explain the situation to them. If, however, the problem appeared only after the system was out of warranty, then there's probably nothing a CR rep could do for you.
It's a long shot, but you could try upgrading your system to Snow Leopard. It's just dimly possible that the newer drivers might work around the problem. No guarantees, but it's a relatively inexpensive thing to try.
Regards.