If you're looking from it purely in terms of functionality, sure. An RG will play alt rock, country, jazz, shoegaze, blues, new age. Whetever you throw at it.
In terms of whether it's the optimum guitar to help you get the tones you want, that's a little more questionable. Sure, it depends on the amps and pedals you use, how you play it, maybe even the pickups which can be swapped out of course. But there are tonal qualities of the instrument that may not be suited for a certain genre. It'll be pushing it to expect a plinky Fender Jaguar to coax out the smooth, rounded tones of a Gibson ES175 jazz box.
In terms of aesthetics - there is a link between music styles and fashion, you can't deny that. And the instrument you play is, by most people, associated with their holistic impression of the genre, both in the look and sound. So yes, if I saw Bruce Springsteen strap on an RG instead of a tele, I'd be pretty darn surprised. And likewise, if some Pitchfork-worthy indie rock band was suddenly caught playing a pointy Ibanez, the card-carrying scenesters would be sniggering.
Ask yourself why you like the RG - if it's because to you playability trumps tone, or somehow the design appeals to you, and you really don't care what others think, then go for it. But don't forget that a guitar is also an extension of your personality and image. People also look at that as it forms part of the complete impression they get from you and your music...so don't be surprised if some folks might not take you seriously, just because of your guitar. Shallow? Yep but dem's da breaks.
