pes-
You've narrowed the field down to some great choices. I don't think you can go wrong with any of your mentioned brands. I own an older RG, and it's great. I also own a ESP, and it's awesome.
My new #1, however, is a Fender Standard Strat with a humbucker in the bridge. It fits me and my playing style very well. It's not perfect, but for $399.00 it's an excellent value for the money.
The best advice I could give you is go down to your nearest mega-huge guitar store and play each one of the brands you're looking at. Buy whichever one fits you the best, and is within your budget.
Then, take lots of pics and post up on thefret, so we can "oooh and ahhh" over your choice.
Almost every name brand manufacturer puts out a guitar under $500.00 that will serve you well. I've even played some Squiers that felt like much more expensive instruments. You might even want to give their Vintage Modified Strats a shot.
Your guitar tastes and style will change over time. Don't feel like you need the bestest, most flashy guitar out there, when there's a value model that will do the same job.
Good Luck!