FiiO will be releasing a lot of new and exciting gear in the coming months and years. A lot of information has been released in various threads so I thought it would be helpful to combine them in a central location and keep it updated for reference.  I did this on my own based on what's been publicly released by FiiO so if any of the information is wrong or out of date, let me know and I will fix it.
 
Please do not discuss the products or make feature requests in this thread - please use their respective threads in the forums. Please only use this thread to suggest corrections on the information listed here. 
 
E6 - Portable Headphone Amplifier
Price: Under $30
Release: 8/25/2011
Head-Fi Thread: http://www.head-fi.org/forum/thread/566351/fiio-e6-story-of-the-tiny-amp-continues
Works With: Any DAP with a line out or headphone out.
Known Features: Smaller and lighter than the E5, uses all-plastic enclosure instead of aluminum. Comes with removable plastic clips. 64-step electronic volume control with hold-button. Three EQ profiles for bass boost 3dB, bass boost 6dB, and 3dB input attenuation. Built in rechargeable Lithium Ion battery with 10 hours of use per full charge. Mini USB charge connector. 
Specifications:
Output Power: 150mW (16Ohm), 16mW (300Ohm)
SNR: >=95dB (A weighted)
Distortion: <0.009%(10mW)
Frequency response: 10Hz ~ 100kHz
Headset impedance: 16Ohm ~ 300Ohm
USB power: DC 5V/500mA
Power supply: Internal LiPo battery
Play time: 10 hours
Size: 41mmx40.2mmx9mm
Weight: 16g
 
E10 - USB DAC and Headphone Amplifier
Price: ~$80
Release: October 2011
Head-Fi Thread: http://www.head-fi.org/forum/thread/559380/e10-new-usb-dac
Works With: Computers, notebooks, or other devices that support USB audio output
Known Features: USB receiver: TE7022. D/A converter: WM8740. Volume control: ALPS pot. AMP section: AD8397. With gain control, bass boost, USB-COAXIAL output, line out and headphone out.  No internal battery so the E10 depends on USB for power. The headphone jack is 3.5mm. The coaxial digital output can feed SPDIF digital audio to an external DAC or downstream device.
 
E15 - Desktop USB/Optical/Coaxial DAC and Headphone Amplifier
Price: ~$290
Release: NA, expected sometime in 2011
Head-Fi Thread: http://www.head-fi.org/forum/thread/536552/fiio-e17-speculations/45#post_7352886
Works With: Computers and any source with a digital audio output. Also provides RCA inputs to work with analog sources.
Known Features: USB 24BIT/96K, Optical/Coaxial 24BIT/128K. Input: USB x1, Optical x1, Coaxial X1, RCA X 1 or 2, Output: RCA line out, 6.5mm Headphone out. DAC: AD1955 or PCM1798. Amp section: TPA6120 ( same as E9). Volume control: Alps pot or digital volume control (WM8816 or TA3110). The Sound will different with E9 when work as DAC, and a little different with E9 when work as amp only. 
 
E17 - Portable USB/Optical/Coaxial DAC and Headphone Amplifier
Price: ~$190
Release: NA, but E17 will be released sometime after the E15
Head-Fi Thread: http://www.head-fi.org/forum/thread/536552/fiio-e17-speculations/120#post_7665597
Works With: FiiO X3 - provides better DAC and amp than X3's internal DAC/amp, FiiO E9 - provides DAC capabilities
Known Features:
A high bit-rate USB/Optical/Coaxial DAC and a high quality headphone amp, in a battery powered portable form factor. Designed for portable use with portable digital-out sources, especially the X3 DAP as well as computers, the E17 offers at least 96kHz/24bit support through USB and 192kHz/24bit over optical/coaxial input. Shares the same basic form factor as the E7, so it is compatible with the E9's dock system. It will use the same amp design as that of the E11.
 
X3 - Portable Digital Audio Player
Price: $150~$170
Release: October 2011?
Head-Fi Thread: http://www.head-fi.org/forum/thread/528916/the-fiio-x3-thread-upcoming-fiio-dap
Works With: FiiO E11 - E11 provides better amp section. FiiO E17- E17 provides better DAC and amp than X3's internal DAC/amp
Known Features:
Please see first post in above thread for main features. This player will not have a removable battery.
 
 
 
Please do not discuss the products or make feature requests in this thread - please use their respective threads in the forums. Please only use this thread to suggest corrections on the information listed here. 

Can't wait for the E17!!

I think you should update this to account for the E15 desktop DAC/Amp

There should a bit more info on the E6 and the E15