Which Helicopter should i get?

As a fair but not great r/c heli pilot who owns a dozen or so helicopters, here's my $0.02 worth.

Your first decision is what type of heli to buy. There are three types in the batch you've listed above; co-axial (two counter-rotating main blades like the Walkera 5#10 above), fixed pitch (like the Falcon 40), or 3D (which most of your proposed heli's are … like the EXI 450LE)

I have and have flown helicopters like each of these. Here's my take:

Co-axial: easiest to fly and cheap, but limited in that they can't perform prolonged forward flight or any acrobatics

Fixed pitch: harder to fly, cheap, no acrobatics

3D (Collective Pitch): harder to fly, most expensive and hardest to set up, but most versitile (with practice, these can do anything)

I'd recommend:

Co-axial: if you go this route, I'd buy an E-Flight Blade MCX. It's tiny, perfect for flying around the house, and is AMAZINGLY stable (even for a coaxial heli). If you want something a little bigger, try either the E-Flight Blade CX2 or E-Sky Co-Lama V4.

Fixed Pitch: I'd skip it…

3D: For starting out I'd go with the Eflight Blade 400 because it has relatively inexpensive replacement parts. Alternatively, I consider the Thunder Tiger Mini-Titan E325 or the Align TRex 450. All of these are well built, are widely available, and have lots of dealers stocking parts.
Bear in mind that all of these are sold in varrying degrees of completion… all need a motor, speed controler, battery, 3 cyclic servos, gyro and tail servo. These electronics can run $$, so don't get sucked in by something that costs $60 (and may cost $400 to complete). Read the fine print and understand what quality components you're buying (I ended up replacing all the servos, gyro, and battery on my first heli within weeks).

Also, if you're going to go all-in along the 3D route, start by buying yourself a decent transmitter that you can grow with. I'd recommend the Specktrum DX7 (great) or JR9303 2.4Ghz (best) if you have the cash (if not the Specktrum DX6i is good too).

Finally, buiding these things (other than the coaxial helis) can be a bit tricky and set-up is critical if you want to successfully fly. I'd spend some time on the r/c heli boards (runryder and helifever are good) and/or find a local hobby shop that caters to heli pilots.

Ok, that's it… good luck!
References :
RC Heli Boards:
http://www.helifever.com/
http://www.runryder.com/

Other good on-line vendors I've used:
http://www.heliproz.com/
https://www.helidirect.com/index.php
http://www.deeteeenterprises.com/home.php
https://www.amainhobbies.com/index.php
http://www.hobby-lobby.com/

Some of my Helis:
Trex 450 SE V2, Trex 450 SE, Trex 450 X, Copter X 450
Mini-Titan E325, Quick EP-8, E-Flight Blade CP Pro, Ikarus Piccolo, E-Sky CoAxial Dauphin, E-Flight Blade MCX

I went on http://www.rcgroups.com and looked under Mini Helicopters. There are several to chose from. I fly a Honey Bee MK 3, fixed pitch as a trainer. There is a big difference between a coaxial heli, which is pretty easy to fly but doesn't have a tail rotor and a fixed or collective pitch heli with a tail rotor. With a tail rotor you have to train your left hand, so it depends on what you want and your experience level. Also, if you have no heli experience you will crash and you will need parts - this is a big consideration. Everyone will tell you that flying a heli is not easy! The parts for my Honey Bee are pretty cheap.
References :