I've got the 32gb 3gS.
1.) Upon receipt of a text message, most of the time, it sounds the tone at the time of the receipt, sometimes several minutes later, sometimes both (one text, two alerts a few minutes apart).
2.) Occasionally (5-6 times in the last two weeks), if I'm on the phone with someone, at the end of the call, the iPod will start to play a random track from the '[all]songs' list (which I never use). This happens when I was not listening to the iPod prior to the call. The song played will not have any correlation to the last song/playlist (alphabetical/next song on playlist/next playlist) that I listened to when I was using the iPod.
3.) I have WiFi turned off, and yet it shows a connection sometimes when near a node when it should remain 3G. This is in spite of the fact that there is a strong AT&T signal in the area.
Sidenote: Is there a way to temporarily disable GPS? I can't find anything in the 3.0 users document or any undocumented features list.