Do you currently use a DD receiver? Do you think maybe you'll be going strictly analog two-channel at some point? I think you'd be better served with the performance gains unless you can really think of a use for an internal crossover.
I definately agree with Jack. Unless your going with some really unique setup then a good avr's controls will far outweigh a subs. BTW SVS has some great deals in thier b-stock right now.