Been using my Go-pro Hero 2 for about two years now and my dad has been using his Go-pro 3 white editon for about one so I have a fair bit of experience using them. As long as you use any SD card from a good brand that uses quality NAND Flash in it you should be fine. Althought some times it just likes to be a PITA and not like some brands over others, but I have used Sandisk and Kingston in mine and have no problems and as Adam3088 has said above me he has had no problems with Samsung brand SD cards so just stick to the good brands and you'll be fine. Here is a link to all three that can confirm work.
http://www.amazon.co.uk/Samsung-UHS-I-CLASS-Micro-Adapter/dp/B00J29BR3Y/ref=sr_1_1?ie=UTF8&qid=1420232389&sr=8-1&keywords=class+10+micro+sd+card
http://www.ebay.co.uk/itm/KINGSTON-MICRO-SD-SDHC-MEMORY-CARD-UHS-1-CLASS-10-32GB-/231319878940?pt=UK_AudioTVElectronics_PDAsAccessories_MemoryCards&hash=item35dbbd3d1c
http://www.ebay.co.uk/itm/32GB-SANDISK-MOBILE-ULTRA-UHS-I-MICRO-SDHC-MEMORY-CARD-WITH-SD-ADAPTER-/351022711395?pt=UK_AudioTVElectronics_PDAsAccessories_MemoryCards&hash=item51ba958263
As far as cases go I just use the waterproof mount with the skeleton door which has been hit direct on the lense with BB's and has not broken. Once it was point blank range coming round a corner and it has not broken. For mounting, I use the gopro helmet NVG mount then place the Go-pro into upside down recording mode, which works great here is the link.
http://www.ebay.co.uk/sch/i.html?_odkw=gopro+helmet+mount&_from=R40&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313.TR6.TRC2.A0.H0.Xgopro+NVG+helmet+mount&_nkw=gopro+NVG+helmet+mount&_sacat=0
(Shameless plug. If you wanna go see my airsoft gameplay footage which is taken with my Go-pro Hero 2 here's the link: https://www.youtube.com/user/UndieingLust/videos)