Although I'm quite new to helicopters I will be the first to lay my money down on a 450 size version of the Sikorsky X2. Seriously.
Update: There was a Chinese company producing a 450 size copy but the company folded and shut down their website before they worked out all the bugs in the first batch of models sold. Walkera has a 250 size version on its website but it is not available for sale as of this date.
Programed my DX7s per RCHELICOPTER.COM's Getting The Most Out Of Your Blade mSR/X & 120SR and motified/protected the tail rotor motor wiring with heat shrink tubing. I need to adjust the rotor blades a little more though.
And still struggling to get a smooth start into a hover.
Update 3 June: I need to get a bigger apartment or improve my flying skills. I've managed to get a hover and keep it fairly stable for 15-20 seconds before it gets away from me. On the plus side it's a tuff little bird that is still in one piece after bouncing off bar stools and table legs a few times.
Update 4 June: I have three 500mAh batteries, (1) E-flite 12C and (2) Tenergy 15C, and each time I change batteries I need to retrim. I'm told this is typical. I have managed to increase my hover time to 3-4 minutes so I am making progress.
Update 6 June: I seem to have it sorted out pretty well and can tail-in hover for a full 5 minutes. I think the new rotor blades helped.
Update 15 June: My apartment has gotten bigger. Yup. That must be it.