2000 or less : best choices for mains?

I'm a great partisan of Paradigm, but I have to agree that the North Creek Rhythm will blow it away. HOWEVER, you'll have to add a sub if you want full range response because the North Creek, while it offers wonderful mids and highs, will chop off the bottom octave or octave and a half of the music.

will

Paradigm Studio 100. You may not need a subwoofer. Listen, don't read.

Yes, you definitely DO need a sub with the Studio 100's. I've sampled them many times with and without a Servo-15. Night and day...

It sounds like you have a H/T setup, so you will need to stay with paradigm or consider replacing all 5 speakers. However I don't think the problem is the speakers, it's your reciever. 70 watts is not enough for the studio 40's. You will find they are capable of quite a bit more bass when you improve your amp. Try going to B&K or outlaw audio for their pre/power amp combo. If you go used you can easily stay under 2k. If money's tight, the H/K 2.0,2.1 combo can be had for about $800, which will blow away any reciever except maybe the B&K. Then you will have enough left over for a used servo 15 or hsu's new VTF-3. This will have a far greater impact then upgrading to the studio 100's. let us know how it all turns out-