You covered a wide range there, what's the top end of your budget? I don't think that we can make a meaningful suggestion without know how much money you're expecting to spend.
The Primare matches extremely well with B&W speakers. I just heard the Primare I30 driving a pair of B&W 800D's at my audio dealer (Audio Connection, Verona, NJ) and was shocked at how good they sound together. If you are near New Jersey you should go and listen to the combination for yourself. Your own ears will be the best judge as to what works for you.
You might also consider the Bel Canto eVo2i. I have owned several integrated amps in your price range and the Bel Canto is a winner for me. Not sure how it will mate with the B&Ws but it worked exceptionally well with my Proac Response 1.5s. It does have the required balanced input and a pre out, both prerequisites for me.
Just the other day I received an email from a fellow Agon member who purchased the eVo2i after seeing several recommendations. He thanked me for the rec. I thought that was a nice touch.
If you like open top end with nice uncolored sound I would second Ayer Integrated recommendation although it is very efficient it outputs 60W only (not sure if that is enough for you).
Krell KAV has very good bass but not much else, treble will be artificial and will be overwhelming the rest of the music. Very unbalanced sound suitable mostly for movies.
CAudio 840 is unimpressive in every respect, rolled off on treble and poor soundstage and realism.
For 2500, you can pick up a used Naim Nait 5i integrated and Naim CD5i-2 CD player and get incredibly musical sound and great system synergy. (The new CD5i-2 is significantly better than the original CD5i.) Even if you keep your current CD source, the Naim Nait 5i is a superb integrated. My experience suggests that mixing and matching of components is a bit of a gamble. The Naim combo will bring musical satisfaction and just might get you off the crazy audiophile equipment-switching merry-go-round...at least for a while.