Dude the RROD is the past. The 360's available at retail now are way more reliable then the past 360's.
I feel your pain. I had my swapping of consoles before. I had a Xbox 360 traded it in for a PS3 then traded in the Xbox 360 then traded that 360 in for a 80GB PS3. Settle with that and the following week I bought a Xbox 360 Arcade. The forums alone had me going crazy because I couldn't choose which console to represent so I ended up buying all three consoles and I'm satisfied other then having to buy games for all three consoles!
So again if your looking into getting a Xbox 360. Get it, now is the time they are extremely reliable and they have a reliable chip set/motherboard installed in the them. So no worries for your 360 RROD on you.