For me, the biggest switch was from my old KPS88 to the Prince TT Warrior.
The racquet was so different from other frames that I used before - utterly low powered. Gave me huge confidence to go for shots.
This was the racquet that turned me from a recreational highrisk attacking player to a consistent competitive player.
Wilson BLX Blade 98 :: Luxilon M2 Pro @ 50lbs