Why do you want two Macs? 15" MBP + 23" LCD, max the RAM, get Applecare.
One other thing to head off arguments - even if you convince me that you need two Macs (not bloodly likely), why on earth would you buy both Macs at the same time? Space out the purchases - buy one 18mos later so it's a more advanced architecture, etc. Then upgrade each one every 3 years. That way you always have a machine (desktop or laptop) that is, on average 0.75 yrs old.