(Sorry for ripping off your style here, Julio)
Rob Trujillo of MetallicaCareer
He played in a few local bands before joining Suicidal Tendencies (in 1989) and fellow Culver City native, Rocky George, the guitarist for the band at the time. Robert replaced the band's second bassist Bob Heathcote. He is responsible for adding in funk influences to the band seen prominently on albums Lights...Camera...Revolution! and especially on The Art of Rebellion. He eventually turned bandmate Mike Muir on to funk music, and the two formed Infectious Grooves to play more funk oriented music.
He was a member of Ozzy Osbourne's band for a number of years starting in the late 90s. Trujillo was the subject of controversy for rerecording Bob Daisley's bass tracks on Osbourne's albums Blizzard of Ozz and Diary of a Madman due to Daisley's claim of not receiving proper royalties. This achieved additional notoriety for giving no notice on the outside of the CD to the buying public that they were not purchasing an original recording.
Robert Trujillo became Metallica's bassist on February 24, 2003 after auditioning for the band and fitting in with fellow band members James Hetfield, Lars Ulrich, and Kirk Hammett. Trujillo received 1 million dollars from the band as an advance on the percentage he would earn by being in Metallica. His audition and hiring appear in the documentary film Some Kind of Monster.His debut studio album with Metallica will be Death Magnetic,which will be released in September 2008.
Also in 2003, Robert was seen playing an upright bass in the Nickel Creek music video, Smoothie Song. However, he did not play bass for the band during the song's recording.
Trujillo is primarily, but not exclusively, a fingerstyle player. He has been known to play with a pick for some of his work, primarily recordings and live playing with Ozzy Osbourne and Black Label Society. In order to achieve the attack and speed of pickstyle playing with his fingers, he has developed a fingerstyle technique which involves using both plucking fingers in a down-and-up motion, or sometimes using three fingers to attack the strings instead of the more usual two. It should be noted that Trujillo's predecessor in Metallica, Jason Newsted, was almost exclusively a pickstyle player, while the late Cliff Burton, Newsted's predecessor and bassist on Metallica's first three albums, played fingerstyle exclusively.
Trujillo is also a very skilled slap bass player, as ably demonstrated in his work for Suicidal Tendencies and Infectious Grooves, where he used the technique extensively. He usually takes an extended solo in Metallica's live shows where he utilizes many of his different playing techniques, as well as using various effects.
Trujillo is also a skilled Flamenco Guitar Player.
With Metallica, he is most often seen to play Fernandes Guitars Gravity 5-string basses, particularly a model with a silver finish, blue flame decals, and EMG pickups. He also has a signature bass model, the Sonus RT, manufactured by Zon Guitars. Prior to Metallica, he was most often seen to play Tobias, ESP and Musicman basses (all 5-strings), as well as a Fender Precision Bass with Black Label Society and Ozzy Osbourne. As of May 2008, Robert has also been seen sporting a Yamaha TRB5-P2 5-string bass for live work, although there is no official word on whether he is now a Yamaha endorser. For amplification, he uses Ampeg amplifiers and cabinets. Also, Robert recently collaborated with Jim Dunlop to create his new Icon signature bass strings - these strings are taper-core stainless steel, in gauges 45-130 (5-string).
Jason Newsted of many, many bandsJoining Metallica
Following the death of Cliff Burton in September 1986, Metallica began a search for a new bassist. Newsted auditioned for the part along with roughly 40 other musicians, and in winning the role, his first live performance with Metallica was at the Country Club in Reseda, California. However, initiation into the grieving band did not come easy, as Newsted was often subject to pranks and ridicule which increased as time went on. He debuted on the group's fourth studio album, ...And Justice For All, which was subject to controversy and criticism for its poor production - namely its lack of identifiable bass. Newsted claims this was further hazing on the part of Lars Ulrich and James Hetfield. The album nevertheless reached No. 6 on the Billboard Charts and projected the group to higher success.
In 1991, Metallica released their self-titled album, better known as The Black Album, which would launch Metallica into their greatest level of stardom. After much touring, the group took a long-needed vacation and, when they returned, surprised fans with a new sound in 1996's Load. This was followed by ReLoad, Garage Inc., S&M, and the popular single, "I Disappear." In 1998 Jason contributed to the album Psyence Fiction by the UK dance outift UNKLE.
In 2000, Newsted co-founded a side project known as Echobrain. They entered a studio in May to rerecord their demos with help from several musicians including Newsted's then-colleague and Metallica guitarist Kirk Hammett, and former Faith No More guitarist Jim Martin. The project was funded by Newsted which he later claimed he lost a great deal of money in. The fact that Newsted began to focus his efforts on a side project created tension within Metallica.
Unfortunately, there is very little info about Jason on Wiki. Feel free to take into account any and all factors, including overall musicianship (read: skill on other instruments), lyric writing, vocals, etc. Keep in mind; the band as a whole is not necessarily a good indicator of the single musician's skill. Vote/rant away.