Need Hi Eff, Omni-directional Speakers

Duevel Planets used?

Bose 901 s used are very reasonable.

Don't forget ohm speakers.

OHMs might sound nice and the price could be right but are not hi eff and 15 tube watts alone may not do them justice. Adding a well integrated powered sub might work if it were needed.

Another +1 for Mirages. The Duvels may well have inspired Mirage's Omniguide-based speakers, but Mirage slants the mounting baffle forward for a 60/40 mix favoring the front. I have been happily living with Mirage OMD-15s for 3-1/2 years. They're a small floorstander that shares the OMD-5's mid/tweet assembly. The OMD-5's were originally priced at $750/pair; at Vann's $338/pair they're a stone cold bargain, especially if you pair them with some modest woofers.

Another approach that's a bit more money is to move up to the Mirage OS3FS compact floorstanders. They're about $998/pair at Vanns.com, but they're open and effortless, more sensitive than the OMD-5s with excellent dynamic range. 93 dB in-room efficient with 175 watt power handling. For the same price you can also get the OMD-15s, a small self-sufficient floorstander. In the Vann's closeout you can get these (originally) $2500/pair floorstanders for $998/pair.

You can't lose with any of these and they are all unobtrusive while having unusual ability in filling a large space with sound.