PC Release Date
So UbiStore says the release date is Q1 2011. When is that exactly?
Well Here: 
Quarters are important because all public companies must report their results on a quarterly basis.
You'll hear the following abbreviations:
Q1 - January, February, and March
Q2 - April, May, and June
Q3 - July, August, and September
Q4 - October, November, December
Basically, each website posted a different time/release date. Why? Because they all estimated the release date.
- IGN says ACB will come out for Brotherhood on March 31. This is because thats the latest, that Ubi can release it. No matter what, it will come out before that date.
- Gamespot said its coming out Feb. 22. Thats basically near the middle of Q1. Its a good estimate of the time it may come out. Still, right now, its hard to beleive that. Ubisoft has given no intimation of how the development of ACB for PC is going.
So, we can assume, based on the delayed release dates of AC2 (an extra 112 days taken to release it on PC)..............
The release date of ACB for PC will be: Tuesday, March 08, 2011*
*If it takes 112 days aswell, this will be the date. 
March 8th is also the release date for Dragon Age 2 for PC. This means, Ubi is screwed. 
It has to make a big revolutionary announcement for Assassins Creed Brotherhood if it wants to make a moderate amount of profit for PC players.
This is not going to end well.
I'm contemplating getting Ac:B for the PC. I've recently become fed up with my xbox 360's yearly fee of $60. costs a fortune in the long run. Ps3 is an option...but the slow loading times would really need some getting use to.
Something about playing with mouse and keyboard appeals alot to me. I havn't fully decided to become a PC Gamer yet..though I'm leaning towards it.
My local gamestop says on Feb22. And they're usually pretty consistent about dates. I doubt Ubi will want to push it back even further.
I have been expecting April, but your estimation of March 8 sounds sound. I have already pre-ordered DA2 (Bioware Signature Edition), so Brotherhood will wait until I finish that (at least one play-through). Then, maybe it will have dropped $5-10 in price by that time. Then, I will be very happy assassinating Borgias.
EDIT:
-----------------------------------------------------------------
http://www.pcgamer.com/2011/02/11/assassins-creed-brotherhood-pc-exclusi...
"Ubisoft Germany have released a video showcasing the PC-specific upgrades, which includes increased draw distance and improved lighting, as well as improved character detail, reflections and more detailed environments. Support for Eyefinity technology will let you display an image across three monitors at a maximum resolution of 5760×1080, providing a great view of Assassin Creed: Brotherhood’s panoramic cityscapes. You can see footage of the game running with Eyefinity two thirds of the way through the video posted on the Ubisoft Germany site."
Still no confirmed date.
This is quite interesting. Assassin's Creed: Brotherhood...in 3D?
http://www.joystiq.com/2011/02/10/assassins-creed-brotherhood-for-pc-get...
Assassin's Creed + 3D = Win.
However, it also = money-making scheme.
I watched the vid on the official Ubi site. My German isn't that good, but I got most of it, I think. Basically: yes, there will be 3D, yes, there will be Eyefinity, yes, there will be better graphics. They've kept the minimum system requirements to the same as AC2, though, they just upped the max. 
Fucking 3D? Best they can do?
Dam Ubi barely made the regular specs of games now-a-days. Almost every game being made is going to be 3D for PC. Ubi hasn't done anything special.
If they can fix their fail optimization.. mabye they got somewhere. Ubi's trying its hardest to hit the bare minimum for todays PC games.
It has now been confirmed as March 17 in North America and March 18 in Europe (and I assume Australia).
A number of websites reported this news today. Here is one:
http://pc.ign.com/articles/114/1149915p1.html
The PC version is now available in both Europe and North America.