I'd preorder in this order (if the only system you own is a PS2):
1. GTA: SA (Can't go wrong with this series)
2. GT4 (going to be awesome, but the competition is coming up close behind them. This year there is alot of superior racing games)
3. WWE: RvS (just got done with the beta & not much movement forward. It's still great...but I expected more)
Now, if you also own a Xbox I would preorder WWE:RvS. Why? Well, it's going to be a while before Wrestlemania come out on the Xbox. And, since Yukes isn't doing Wrestemania then it could end up meh. As far as GT4, I'd wait to see how Forza unfolds- there's an aweful lot of hype it's got to live up to. Now as far as GTA:SA...well, there seems to be a lot of rumours about it coming to the Box in March of next year. That would suck to buy it on the PS2 and have it come out less than 6 mo. later on the Xbox. Nothing against the PS2, but when games come out multi-console I prefer them on the Xbox.