might as well start off with i have owned a quad, and then merged everything over and made up a hex, so i suggest going hex for fpv for the following reasons
quad, as great and light as they are, if a motor fails you WILL fall out of the sky (it has happened to me prop and motor) with a hex if a motor or prop fail there are motors either side to back it up and keep it flying.
with that in mind, once you move onto fpv, you will have
a camera on-board (i recommend a gopro, it is superior quality over most cameras, it can record and output its full quality)
http://www.digitalrev.com/product/gopro-hero3-silver-edition/MTAwMjE4OQ_A_A
video transmitter (recommend going fatshark for all of the video rx/tx and goggles)
http://www.hobbyking.com/hobbyking/...o_Transmitter_FatShark_compatible_600mw_.html
these things cost money, around $400 worth and if that falls out of the sky it might break and you dont want that happening
i suggest you get the apm2.5 board, it is far superior to most flight control board (better sensors, i know iv had the kk2.0 and miltiwii board)
here
http://www.baskindustries.com/aerospace/store/products/ardupilot-mega-2.5.php
or here
http://www.rctimer.com/index.php?gOo=goods_details.dwt&goodsid=818&productname=
keeping in mind this place i dont think sell the case for it, the bask industries do and i got it separately off them pretty cheap
you will want to get carbon reinforced props, they are nice and strong the size is up to you, i use 10x4.5
http://flyduino.net/Multikopter-Propeller-CW-CCW_7?jtl=v
get the fatshark dominator goggles and the fatshark 5.8ghz receiver and the circular polarized antenna
http://www.hobbyking.com/hobbyking/...inator_3rd_Generation_modular_FPV_System.html
http://www.hobbyking.com/hobbyking/store/__19447__FatShark_Dominator_5_8ghz_Module_.html
http://www.hobbyking.com/hobbyking/store/__27750__5_8GHz_Circular_Polarized_spiroNet_Antenna.html
25amp speed controller should do the job if your using a normal motor, 40amp if you have the cash to splash
http://www.hobbyking.com/hobbyking/store/__2163__TURNIGY_Plush_25amp_Speed_Controller.html
these are the motors me and my other 2 mates are using and we havent had any problems with them (except a few bearings failing prob due to a crash here and there)
we have run a tonne of packs through these.
http://www.hobbyking.com/hobbyking/..._28_26A_1200kv_250w_short_shaft_version_.html
me and one of my mates are using these frames, they are great for hiding the fc board and receiver etc between the frame and it looks super neat.
well enough of that, here are pics of mine. these photos are a bit old but not much has changed.
View attachment 23466
View attachment 23474
View attachment 23482
oh and get this gps, as expensive as it is i have used 2 and my mates have this one and it is heaps better. the gps positioning and holding from it is near spot on.
http://www.hobbyking.com/hobbyking/..._Module_w_Built_in_Antenna_2_5m_Accuracy.html
oh and make sure you dont plug **** in the wrong way, this stuff isnt exactly cheap so you dont want to be forking out money and or waiting for a silly mistake, i have blown up heaps of crap cuz of wrong wiring (from factory and my own fault) and its frustrating, use a multimeter and play it safe with everything....
here is your library from now on...
http://code.google.com/p/ardupilot-mega/wiki/APM25board