A few things to check when buying an Ibanez -
try getting a japanese one. the korean are actually much better than they used to be a few years ago but still... the Indonesian are really not what i'd go for...
Don't go for a guitar for its looks - the trend in cheap guitars is to make beatiful guitars using all sorts of techniques to make people buy more. I've seen some beautiful korean guitars that have nothing more than their looks... I do have a korean ibanez acoustic and it's definitely OK for it's pricetag, and more.
The Ibanez tremolo systems - go for the better ones - Lo-Pro for example. some people have trouble with the Lo-TRS (i have one and i set it up quite well, though).
The S series can be very misleading - they're very comfortable, very light, but sometimes you need that thick fender-style neck... only go for it if you're absolutely certain you like it. I think the RG is a smarter buy because it has more wood. the S series guitar are just to thin to get enough "wood" in the sound sometimes, or so it seems.
Pickups... generally speaking, i don't like them. the Ibanez stock pickups are usually too "weak" for me. the DiMarzios can work but they only put them in the expensive models.
if you have the RG320 and you really really like maybe you'd like to change the pickups... but it depends on the guitar and its condition.
Always remember, you only get what you paid for. the only Ibanez guitars that are great from the start are the expensive ones - the Prestige (depends...) and the signature models...
I've had
my ibanez s470 since 1996 or maybe sooner. didn't like the stock pickups. i really liked the neck and size back then but now i don't really like them. after changing the pickups to some nice (expensive) ones it sounds much much better.