Regarding Luke Donald, an average driving distance of 275 yards isn't bad really, especially when his accuracy and consistency are taken into account.
I know that lessons and club-fitting are always recommended, but last year I spent £25.00 to be fitted to a 10* Diablo Edge (£190.00) despite having a swing-speed of approx. 80mph. So I find myself hitting a 17* 4*wood (now obsolete so cost only £80.00) both straighter and significantly further than a driver.
I've also thrown money at lessons to simply be told that I need to "release the club-head / roll my hands over" to prevent a straight-fade... and that a draw will travel further because it's struck with top-spin!
Best money I've spent on Golf merchandise was the Stack & Tilt book by Bennett & Plummer. I've found the section on diagnosing faults to be more valuable than any lesson that I've paid for.