Everybody needs 6 guitars.. how else are you gonna play with 5 others? 
lol... in all seriousness it's pretty easy to accumulate guitars if you keep buying the different versions. I have a PS2 guitar from my pre-XBOX GH1 and GH2 days... then I got GH3, and the rockband 1 bundle... and I'm going to get the GH WT bundle.. so I'll also be up to 4 different guitars and I've never bought an extra guitar.
Each new version of the guitars seems to have enhancements... like the solo buttons in the rock band guitar, and now the slide panel thingie on the GH:WT guitar... it keeps people wanting to buy the bundles and the guitars just keep piling up.
lol... in all seriousness it's pretty easy to accumulate guitars if you keep buying the different versions. I have a PS2 guitar from my pre-XBOX GH1 and GH2 days... then I got GH3, and the rockband 1 bundle... and I'm going to get the GH WT bundle.. so I'll also be up to 4 different guitars and I've never bought an extra guitar.
Each new version of the guitars seems to have enhancements... like the solo buttons in the rock band guitar, and now the slide panel thingie on the GH:WT guitar... it keeps people wanting to buy the bundles and the guitars just keep piling up.
