Paradigm Reference Studio speakers, without a doubt.
The Paradigm Reference Studio 60 is definitively the best speaker, period.
Even if it's more money for the full set, it's worth it. Get it.

You'll never regret it.
Also, you can get the Studio 60 for less than $2,000 cdn/pair.
For the center channel, why not go with the CC-290, excellent center speaker for only about $400 cdn (deal).
If you're good at dealing, like I am, you'll be able to get those three Paradigm speakers for about $2,000 to $2,500 at the vey max. (but they'll better be the latest version 6). And why don't you try to score a deal for the version 5?
* And why don't you just pick the Studio 20 with the same CC-290 center speaker? Do you have a good sub? The Studio 20 is a fantastic speaker for the price. You can get a pair of these for about $800/pair.
They have plenty of bass, great resolution, full timbral sound, rich, pleasant, natural, deliciously sweet, and just plainly right.
Don't ask me where, that's your job.

And even if they cost more, it still a good deal for quality speakers like those.
Check the second hand market, or send flowers to your Paradigm dealer.
Is your system a 3.0 setup? I really doubt it, you must have already a sub and the surrounds.
Cheers & don't look back (just give them a listen, and you'll hear what I'm talking about).
Bob