Upgrade amp. or speakers first?


I have a Krell KAV 300i, and a pair of B&W N804's, all about 12 years old. Want to upgrade and want to know which should be first to go. The speakers or the amp? I listen to mostly jazz, some small scale classical, and R&B. I am leaning towards the 803D's or 804D's. Will budget up to 8k for amplifier(s). I have listened to some McIntosh, the new ARC integrated and Rotel amps. I recently got an Ayre QB-9 for digital source ( ITunes-Macbook ). Will upgrade, but not all at once. Thanks for any suggestions.
atj2
We have two schools of thought talking here. But both are in agreement that it is the amp/speakers match that counts.
I would audition many different combinations, find the most satisfactory and then begin the upgrade in any order depending on price, mood, dealer's attitude etc. Or would wait and get both at the same time.
Personally I tilt a little towards "speaker school" and tend to think of speakers (and the room)as musical instruments. After all I have Michael Green free resonance speakers - not the last word in resolution and many other aspects of sound reproduction but they play in a very natural way with any amplification I tried.
I would suggest speakers first because you want them to be suitable for your room.
Thanks for everyone's input and advice. One problem that I have run into is determining how any speaker candidate will sound in my system, fed by the Ayre QB-9 in particular. It made my system much more lifelike. I'm thinking that new speakers may sound great at the dealers but at home, they may be too aggressive or forward. Should I take my DAC and computer with me as I audition speakers, or limit myself to the one dealer that already has the DAC. I mentioned that I heard the 804D's in systems without the QB-9 and the speakers lacked that live feeling that I'm getting at home now.