im no expert but here i go i agree with using Tower Hobbies their not always cheapest but they have a big selection.
also
http://www.mcmaster.com/ at the bottom of the page there's a "raw materials" in there they have lots of great stuff like Garolite aka "G10" ive used that for the tail control surfaces (its under plastics) its kinda overkill but ive broken basicly every thing on my plane except the tail. there is allot of other stuff that could be useful but ive never used it.
now about the plane do you know how big your proto is going to be with new batteries they can be bigger but it costs allot more $$$ i personaly hate gas/nitro all three i have owned have had issues but i must have done something wrong so i cant help you there(liability for failure)
the radio is probably the most important thing if you get a crappy one you could get interference which = "crash" then waaaa or $*&! depending on your personality
i recomend this charger
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXMAJ0&P=0
i used it and it can charge basicly anything. most say its complicated to use but i figure if ur build a proto you can figure it out( make sure you figure it out before chargeing batteries because messing up = more $
i would use
brushless electric motors and LiPo(lithium) batteries
the have higher Mah(run time) and higher voltage (speed) but the need a special charger like the one stated above ^ i dont know how big the plane is so cant tell you what exact motors on batteries to try
the another important item is the ESC (elec speed control) theres also VESC v=variable but dont know anything about them
most controlers can only do one motor some can do two
most of the time you use one of these
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXTSL0&P=7
to combine two ESCs using one radio slot ( instead of controling each motor seperately) careful some y harness are for certin radio brands only and are
not universal same goes with servos recomended that the servos are the same brand as the radio
as for servos there are so many that all i can say is get ones with metal gears
theres a ton of information if you need help PM me and i will try to help
Matt