Ok like DVD Players, Bluray players are region specific. Some can be unlocked and some can't. You will have to research which ones can and can't. www.videohelp.com
is the site I used when I needed to unlock my DVD player. I have not looked at the site since I got my bluray player but I have seen others online saying it can be done so I am sure they are a good starting point.
Bluray players will play DVDs and in most cases CDs too.
Be sure to check that it has wireless built in and that it is N-wireless. Some will advertise as "Wireless Ready", dont be fooled by this because you will end up having to purchase an adapter that can range from $40-$100 dollars depending on brand. The N-Wireless is important if you plan to use the player to stream movies wireless. Most bluray player have apps built in like netflix and hulu so you want the best speed available to guarantee HD streaming. Mine has wireless but it also has an ethernet port which is what I use for the best speed and my router is right next to the player so it was easy to cable.
I would go with 2D. The 3D stuff is more expensive BUT if you get a 3d player, they should still play the 2D discs fine.
Pricing really varies but you do get what you pay for. I would ask myself what am I looking for the player to do? Just play bluray or are you in to streaming movies and other things? If so what all do you want to do? That will help narrow down your selection because not all players have the same apps and abilities.
Hope this helps a little but ask away if you have more questions and I will do what I can to help.