I just started a similar topic, but dealing more with launched rides and LIMs. Check it out...
http://www.coasterbuzz.com/forums/thread.asp?ForumID=11&TopicID=7853 If the link doesn't work, it's in the "General Buzz" forum under "Mr. Freeze vs. Hypersonic XLC + LIM Technology / ideas".
I'm really big on the possibilities that exist with launched rides and LIMs. The Arrow 4D is really going to shake things up too, and having S&S in the coaster business is great too.
There are so many new inversions out there too - tophats, cobra rolls, heartline... Speed and airtime are great, but it's the inversions that got really got me into this (ala Shockwave @ SFGAm). I want to see the return of the golden days of the Arrow Mega Loopers - but with the smoothness and comfortable trains that B&M offers. Maybe something like a Hyper-Twister Giga/Mega suspended coaster like Batman combined with Raging Bull or MF.
The more elements, the better... helixes, inclined loops, heartlines, cobra rolls, interlocking corkscrews, tophats, 360 loops, teardrop loops, boomerangs, lets do it all, and do it from 300 ft @ 100 mph !!! :)