mbho > 722 is a really good combo. i personally would upgrade the naks before investing in a nice pre/AD but that's just me.
do you have a budget? the various ua-5 flavors are also a great option for a pre/AD in a single box and has the option of 24-bit. there is also that ad1000 that popped up in the YS today, but the remaining life could be questionable and you have to deal with 12v SLAs.