I'm looking for M80i-QS8-VP150-EP350. Do you think I should go with Denon AVR-2805 or AVR-3805 and WHY ?

I think either would work fine. The 3805 does have a little more WPC but not enough to hear the difference. If you have the $$ to spend go with the 3805 just to avoid the upgradeitus. If $$ is a concern go with the 2805.
I have the 2805 paired with the M60s and I am plenty happy with it.

I guess the major differences are :

- 3805 has a very spiffy remote (nice, not essential)
- 120 vs. 100 WPC (not a huge difference)
- DenonLINK (seems like a real good idea but I don't seem to hear about anyone using it)

Anything else ? Unless I'm missing something, the 2805 seems like an obvious choice unless DenonLINK (running DVD-A and SACD over a digital connection) is important.

Thank's for the answers.

Since i'm new in this world, do the AVR-2805 will be "strong enough" to push the 4 Ohms impedance of the M80i ?

The Denon will do just fine with the 4 ohm load of the M80s.It is rated at 100 watts into 8 ohm,you could expect it to be around 150watts @ 4 ohm.

Doesn't the 3805 have the Burr-Brown DAC...and the 2805 does not?

Can't speak for the M80's, but my 2805 drives my system nicely. I have heard the Denon will handle 4ohms fine, just not sure if that applies to all models...

M60's VP150 EP350 4-Qs8's
Denon 2805

With only a small WPC difference between the 2805 and 3805, I believe that either will handle the M80s fine.