Best Paradigm 5.1 set-up for around $1800

I would build a quality 5.1 setup over time rather than rush to buy all speakers at once. Take your $1800 and buy a set of Studio 20's and a pair of Atoms for the surrounds. You can run a phantom centre and route the LFE signal to your front speakers. Then a few months from now or in the new year buy a CC 490 or 590 which ever you prefer. After that get yourself a sub - a DSP 3200 or 3400. Within a year you'll have a much better system than trying to get everything all at once. I started my 5.1 system back in February and just finished it off on Labour Day weekend with the addition of my DSP 3200. I run a set of V4. Studio 40's and a CC590 with a set of Atoms in the rear. Supplying power is a Yamaha RXV-3900.

Or just take your money over to svs and buy this sick set up.
http://www.svsound.com/products-sys-sts01.cfm

I expect the 20's would hold their own against the 7s in a volume contest presuming you power them with something suitable.

Unless you're in a hurry, I would avoid trying to buy the whole setup all at once with your limited budget. Instead, I'd determine what your needs are (HT, music, gaming, etc) and build a nice setup in stages. If you're into HT, get your front end and a sub and get the surrounds next. If you're into music, get a really nice pair of fronts and then a sub, center, and surrounds. If you're into gaming, get a less expensive 5.1 like the SVS or other options and buy it all at once.

You can look into ID brands that is similar to Paradigm. I have found a lot of reviews stating that the AV123 Rockets and Axiom sound similar to Paradigms. You might want to hit both their forums and see if you can audition them.

I strongly agree to go with the studio series. I own Paradigm Focus v3 and love them. Recently I upgraded to towers in my movie room and put the Paradigms in the living room.

During auditioning speakers I demoed the Monitor 11s, studio 100s,60s, and Klipsch RF80s side by side. The monitor 11s were far outclassed by the studios and the Klipsch.

It was really sad, even my wife thought they were blahh, compared to the others they lacked detail, imaging, clarity. The Monitor series is a big step down from the Studio series. In the end I bought Rocket 850s with the Bigfoot RSC200 center and love them. Id put them against studio100s any day.

IMO, i'd recommend the Studio series if you like Paradigm, Or go ID, the Rockets have a similar sound to the Studio 100s but a little cleaner highs and tighter bass IMO.

As far as atoms for the rear, sure why not, just make sure you timber match the front three, the rears are a good place to skimp on to allow you to get a better front stage, you can upgrade them later if you like.

A good sub is a must, Paradigm subs suck IMO, they get really muddy when pushed. Try SVS, HSu, AV123, or if you're on a budget Partsexpress has some really great subs for low prices.

I run Studio 40s and a CC590 in the front with original Atoms from 1997 in the rear and I have no complaints. For both HT and music the sound is amazing. They even handle high volume stuff suprisingly well. Timbre match the front 3 and you'll be fine. Leave the Atoms in the rear and upgrade them when you have some extra $$$.