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
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.
Take your DAC, computer and amplifier to the dealership. There's no other way to hear the combo unless the dealer happens to have the same electronics.

Otherwise, slow down a little and buy a plane ticket to Las Vegas to attend CES and T.H.E Show in January to listen to a wide variety of speakers (and matching amplification). You'll get a good idea pretty quickly what appeals to you and what doesn't.