What should I upgrade -- speakers or amp?

I'm a relative audio novice who's been slowly building a system over the last few years. I'm considering what to upgrade next. This is what I now have:

B & W CDM 7 NT speakers (2)
Magnum Dynalab MD 208 receiver, 150w
Consonance Droplet CD player (tubed, upsampling)
Sony SCD-595 SACD/CD changer
Kimber Kable Timbre Interconnects
audio store speaker cable

(Two digital sources because I use the Sony for more casual listening, & the Droplet for more attentive sessions. The Droplet was supposed to replace the Sony in my system, but because of the convenience of the changer, the Sony never went away.)

I listen mostly to orchestral/opera, with some chamber music & jazz thrown in. I also listen to FM radio a lot, and live in an area with poor reception. But the Magnum Dynalab has superior reception, even without an ouside antenna. So I'm happy on the tuner front.

I'm considering upgrading either the speakers or the amp.

At the moment, if I go with speakers, I'm leaning towards pre-owned B&W 804 or 803. I'm impressed that most classical studio recordings are made with B&W monitors. And the B&Ws pass the wife acceptance test (the system resides in the living room). I've been happy with the CDM 7 NTs. But I'm open to other speaker suggestions.

Another possibility is to get a new integrated amp. (I have space issues, and also would rather not get into all separate components to avoid unnecessary complexity. I enjoy the equipment, but fundamentally I'm a music-lover, not a gear guy.) In stores, I've liked the sound of the Krell KAV 400xi. If I got one of these, I'd probably use the MD 208 as a tuner only.

But the purpose of this post is to get your suggestions. Which would likely give me the most improvement in my listening experience? Are there other components I should consider?

Thanks in advance for your thoughts, 'goners.