#4 Gareth Bale
Gareth Bale will perhaps remain the greatest enigma for Real Madrid over the last 5 years or so. Despite winning so many trophies at the club, many view his time at Real Madrid as unfulfilled.
This may seem odd, but when considering his purpose was to inherit Ronaldo's throne, it becomes clearer why some think that way about the Welshman. Nevertheless, Bale was instrumental in Real Madrid's 2013/14 season, arguably his best ever, scoring in both the Copa del Rey Final and Champions League final.
He followed this season with another strong showing in the 2014/15 season but since then he has had a mixed time at the club. Injury has plagued his career and one can imagine that he would've been far more successful on a personal level, had his body allowed him to.
Although it looks as though Bale will depart from the club this summer, his heroics at his best moments in Madrid shirt mean he is definitely one of the club's best signings since 2009.