After a 4gig Lexar failed on me I have only ever bought Sandisk I have never had a card failure since.
However I have saved the images from another sandisk card that had been used over and over again by only deleting in camera images they had transferred over to pc using camera software.
When you buy a new Sandisk SD or CF or in some cases a memory stick you will get a free to use code for their recovery software that in my experience is very effective at sorting out a card that can otherwise not be read. So if you buy a sandisk card you will get the voucher and then you can the recovery software a try on the old card.
Its also worth getting into a routine of Putting card in camera and format it in camera then go on shoot, come home and remove card from camera and transfer the pictures over to pc - copy pictures to your "backup drive" you should have one! and then put card back in cam and once you have made sure you have your files and a copy of them, format the car in camera ready for next shoot! Its a faf at first but it has served me very well for a good while now and not one card issue!
We do this same process with all the video cams too and again no issues - over 120 sandisk cards ranging from 8gig to 128gig both SD card and CF cards
Good places to buy are
My Memory
Amazon UK - but only supplied and del by Amazon Never a third party!
Costco have great deals now and then