Houllier got alot of stick at the time for his approach to the academy, but in general he modernised the club from top to bottom, he got rid of the lad culture that had developed (or become outdated), and brought in stricter fitness and dietary regimes.
He put the club back on the map in Europe, we had Germany and Bayern in particular fawning over how good we were - I remember McAllister, Owen, Heskey and Gerrard being singled out for particular praise at the time of the Super Cup and then on the back of the famous England win.
He was never the same after his illness and became indecisive and meddlesome with the team.
In many ways, Rafa's tenure echoed that of Houllier. Great start, increased European standing, and a few cup finals aswell - the CL was massive, but the cup treble was too in it's significance.
Both managers built a title challenging side that could have won the league in any other season, and both failed to maintain that level in the league, through indecision and a frustrating undercurrent of stubborness, that was eventually the undoing of both.
When both went it was probably about time, both tenures had gone stale. It's easy to say with hindsight that we should have done this or that, but we challenged for the title again within 5 years so despite the upheaval in the boardroom, we weren't "finished", like many predicted.
It's taken a while for us to get some sort of European pedigree back - I don't think we fully will until Klopp is back in the CL. That's testament to both managers and their respective success in Europe and dragging Liverpool back amongst the Elite. Both men are tremendous ambassadors for the sport and have Liverpool running through the veins, their devotion to the club since shows how much we meant to them and they should be commended for that. It's time that both were looked back on for the good times.