it depends on what you are wanting to have them stored on. I use USB Flash drives for that now... My vehicles use SD cards so I have some music on them. But all of my music wont fit on them. Music is mainly stored on External HDD's... have 3 2TB usb hdd's full of music. The last one I picked up at Cosco I think. If u don't have that much and want something a little more portable, just grab some Flash Drives, even a 256GB one will hold thousands of songs.
Its bigger than 1TB, but if you want a fast hard drive that you will never run out of space on then you could grab this today: http://www.newegg.com/Special/ShellShocker.aspx?cm_sp=Homepage_SS-_-P5_22-236-971-_-12162015 I hate external drives since now days they all just seem so horribly slow. The only ones I use are a small enclosure with a SSD put inside it. I know it looks shitty and you have to deal with the external power supply, but this seems to be a pretty good enclosure with really fast speeds for external SSD use: http://www.newegg.com/Product/Product.aspx?Item=N82E16817707333 Or this for something that is just overall easier to work with but has a bit less speed: http://www.newegg.com/Product/Product.aspx?Item=0VN-0003-000H1 These stick one of these in it: http://www.newegg.com/Product/Product.aspx?Item=9SIA2F83437296 http://www.newegg.com/Product/Product.aspx?Item=N82E16820211985
How do the sandisk cards compare to the the likes of samsung, crucial and adata? Link: http://www.amazon.co.uk/SanDisk-SDS...id=1455479851&sr=8-1&keywords=sandisk+ultra+2
