SVS or REVEL Subwoofer

I would check out REL's HT lineup.  Obviously great subs, at a very reasonable price.  After my Paradigm sub ($2000) died, I decided that I didn't want to spend that much (just like you apparently) on something that might die in a decade.  The subs cannot be repaired.

The REL HT/1205 MkII (get the newer MKII, not the original version 1), which just came out within the last year, can be found on sale, new, for $699 (from $849 list).

Personally I think that it's a fantastic deal.

Driver: 12 in., 300mm long-throw, CarbonGlas cone structure, inverted carbon fibre dust cap, steel chassis
Low Frequency Extension: -6dB at 22 Hz
Input Connectors: Dual purpose Low Level stereo RCA or LFE RCA
Output Connectors: Daisy Chain Low Level stereo RCA or LFE RCA
Power Output: 500 watts (RMS)

Amplifier Type: NextGen5 Class D

Dimensions (WHD): 16.25" x 15.25" x 17.25"
Weight: 43.2 lbs.

Re: high level inputs vs low level-- I would check some hifi blogs about this.  On whatsbestforum.com, the suggestion is that low level might be the better way to go.  Personally I have not tried this out, but Kal Rubinson, who is a senior editor at Stereophile, says that low level inputs are better to use.

And again, personally I am no longer interested in spending >$2K on a sub that might die in a decade, like my last sub.  That's why I'm suggesting the HT-1205 @$699.