The Samsung Evo brand boasts resistance to water, dust, temperature (entirely happy between -25 and 85 degrees Celsius), x-rays, and magnets. Heck, leave it in seawater for 24 hours, and it’ll still be fully functional.
You can currently grab the Samsung Evo 32GB class 10 microSD card for £9.66 at memorybits.
Transfer speeds up to 48MB/s.
(Thanks to gooeynote at HUKD)