Korn's first and second album, Fear Factory, and Vai were the initial influences for purchasing a seven. Once I found out about the George van Eps my interest in the instrument spiked even more because of the discovered potential versatility of the instrument.
Not really anyone in particular. I just wanted a deeper sound for neo-classical and death metal stuff. I was actually originally going to get a baritone but I couldn't find any that I like, plus I wanted the full range a 7 string has. That being said, hearing God of Emptiness and Where the Slime Live by Morbid Angel somewhat influenced my decision, hah.
For me it was when I met this guy by the name of Narshadda on another forum (www.guitarbt.com). We had these regular jam rounds and monthly competition, and this guy was really good. He was also a 7-string player. I guess he made me decide that a 7-string guitar might be something for me aswell. He also gave me some tips when I just started on my 7-string.
I had been batting the idea around for a few years. I knew Vai had used them....lately I got the Loomis solo cd....and my interest resurfaced. It was just something I wanted to try. I've been playing 6 stringers for over 20 yrs and recently felt like my playing was getting stale. Then, the opportunity to interview Steve Vai came up....went to his house and we interviewed him in the "Harmony Hut" (his home studio) and saw a few 7 string guitars on the wall. I did a little research, followed a few ebay auctions and CL listings, and eventually found a 7620 locally.
A band I was in, in high school the guitarist had an Ibanez Rg7420. I had just bought my 5 string bass. I thought the things you could do were amazing. I moved on from that band after high school and started jamming with another band with my 5 string. The guitarist (my now boyfriend) had never tried a seven. I mentioned how awesome I thought they were and he picked up a Washburn seven (which sucked) later he got an Ibanez. That was about 6-7 years ago and he's still hooked. Now I own a seven. He owns 2 and wants more and possibly and 8 someday.
Matt Bellamy made me think towards sevens, i still need to get one, but nothing out there takes my fancy. Still waiting for some company to build my perfect seven, other than that i'm saving for a custom.
Meshuggah and Bulb...I really hadn't any need for seven but I bought one. I generally suck at guitar playing, but it didn't keep me getting more guitar stuff and different guitars...so I just bought one. Then I bought second. And now I can't stop. Nowadays I really can't recall why I would buy 6-stringers anymore..I wouldn't play them 'cause I don't have any time for them. 7 just feels a lot more better...