Are there any particular synths out there that make good use of the ewi's dynamic expression or should any old thing work if you know how to set it up right? I'm partial to soft-synths (guilty) - would love to try some product demos so I have some dreams to set aside money for!
I use the Yamaha WX7 wind controller. Here's some synths I can personally recommend.
Yamaha VL70-m module. Physical modeling, primarily emulative. Out of production, available used. You really want one with Patchman Music's Turbo chip.
DSI Mopho desktop. Analog. Flexible modulation; you can have the EWI/WX controlling up to 5 different destinations, each with its own amount. The DSI Evolver would also be good (digital/analog hybrid), but I haven't personally used it.
U-he Zebra. Semimodular, can modulate just about anything.
U-he ACE. Modeled analog modular. Can modulate just about anything.
There are many other synths can would work. For FM, I've used Yamaha TX7 (DX7 module) in the past, and fiddled around with Native Instruments FM8.
Check out the wind controller forum at Yahoo.
I mentioned Patchman Music, LLC Online - "The Wind Controller Specialists" earlier. He's a patch author and equipment dealer. There's a good FAQ there about lots of wind controller topics. There's also discussion there and on the wind controller forum about sample-based software, if that's to your taste, and other synths (hard and soft) generally.
Yamaha VL series - VL1 is king
Emu Proteus 2000 series (older Morpheus also has potential but legato mode kind sucks - very fast MIDI though like the newer units)
VsynthXT is also good.
The Patchman forum is a useful source of info but bear in mind they've all drunk the Patchman cool aid. Just get in and program your synths - a bit of trial and error mixed with a good helping of rtfm goes a long way. There is no magic to programming a synth for use with a wind controller.