Welcome to the boards.
There isn't alot of difference quality/power wise from the 2808 to the 3808, but what you are getting with the 3808 is a very nice GUI and handy network connectivity for easy music streaming, along with a couple more HDMI ports. I am probably missing a couple other differences but to me these were the ones that swung me in favor of the 3808.
So far as your speaker choice, you can't go wrong with either of them, both have great sound, but of course I would go with Axiom, best bang for the buck, IMO.
If you are truly new to buying speakers in this area of sonic quality, I would suggest getting out to your local audio stores and try listening to a few or as many as you feel comfortable with. Take some notes on what you think about of each speaker and then go with the ones you feel sounds best to you. You can check the Hearing Things forum here to see if there is anyone nearby that could give you an audition of some Axiom's.
