My 360 got red ring and i was wondering...

if i wait until the 20 gig unit is discontinued til i send it for repair (i have a 20 gig) will the new system i get back be the arcade or the new 60 gig with the hard drive thanks

Your hard drive has nothing to do with RROD. You do not send your hard drive.

The repair center people you talk to on the phone (and plus the instructions you get with the box they send for you to put your Xbox 360 that needs repaired) tell you specificially NOT to include your hard drive and to remove it from your system.

So this is not a way to get a 60GB hard drive.

Just get an fan to go around the back(intercooler) and it will avoid the RROD21lockdown