Ken
First you have to determine how much the data is worth to you.
Then figure out if you have that much and if you risk it with a large data recovery firm who will not guarantee anything. I remember some places that charge a base fee and then a price per MB of recovered files. They may or may not be the files that are important to you. If you have a specific file name they may be able to give you a quote on looking for just that data.
There are a couple of processes that the manufacturer can offer the best odds on.
http://seagatedatarecovery.com/
If you have a real hardware failure “disk crash” where the head is impacting the platter, (ting, ting, ting) the best odds (assuming the platter is not heat deformed) can be for the techs to transfer the platters in a clean room to an identical drive (or a test rig that can mimic one) and copy all the data from the undamaged cylinders.
As a DIY kinda guy I have built a plastic box and glued gloves and fans to it to swap hardware around for my own recovery of a scsi drive I had 9 obsolete units of, and knew I could never afford to pay for the recovery, but that is not something I would ever do as a paid job for anyone else. It took me two weeks and I could only recover about half the files I lost.
Get a quote from several of the places you can find on the web. If you can’t afford their price you can try some of the alternative software. A good forensic disk image (assuming the bios still sees the drive) might be written raw to another disk and then the usable stuff teased out as long a one copy of the file allocation table (or equivalent) can be found.